Floyd's triangle: Difference between revisions

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=={{header|Run BASIC}}==
=={{header|Run BASIC}}==
<lang runbasic>input "Number of rows: "; rows
{{Output?|Run BASIC|There should be one space between the numbers on the last row.}}
dim colSize(rows)
<lang runbasic>input " Number of rows:"; rows
for col=1 to rows
html "<table>"
for r = 1 to rows ' r = rows
colSize(col) = len(str$(col + rows * (rows-1)/2))
next
html "<TR align=right>"
for c = 1 to r ' c = columns
j = j + 1
html "<TD> ";j;"</TD>"
next c
next r
</lang>
Number of rows:?5
<TABLE BORDER=0>
<TR ALIGN=RIGHT><TD>1</TD><TD></TD><TD></TD><TD></TD><TD></TD></TR>
<TR ALIGN=RIGHT><TD>2</TD><TD>3</TD><TD></TD><TD></TD><TD></TD></TR>
<TR ALIGN=RIGHT><TD>4</TD><TD>5</TD><TD>6</TD><TD></TD><TD></TD></TR>
<TR ALIGN=RIGHT><TD>7</TD><TD>8</TD><TD>9</TD><TD>10</TD><TD></TD></TR>
<TR ALIGN=RIGHT><TD>11</TD><TD>12</TD><TD>13</TD><TD>14</TD><TD>15</TD></TR></TABLE>
thisNum = 1
Number of rows:?14
for r = 1 to rows
<TABLE BORDER=0>
for col = 1 to r
<TR ALIGN=RIGHT><TD>1</TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD></TR>
print right$( " "+str$(thisNum), colSize(col)); " ";
<TR ALIGN=RIGHT><TD>2</TD><TD>3</TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD></TR>
thisNum = thisNum + 1
<TR ALIGN=RIGHT><TD>4</TD><TD>5</TD><TD>6</TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD></TR>
next
<TR ALIGN=RIGHT><TD>7</TD><TD>8</TD><TD>9</TD><TD>10</TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD></TR>
print
<TR ALIGN=RIGHT><TD>11</TD><TD>12</TD><TD>13</TD><TD>14</TD><TD>15</TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD></TR>
next</lang>
<TR ALIGN=RIGHT><TD>16</TD><TD>17</TD><TD>18</TD><TD>19</TD><TD>20</TD><TD>21</TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD></TR>
<pre>Number of rows: ?14
<TR ALIGN=RIGHT><TD>22</TD><TD>23</TD><TD>24</TD><TD>25</TD><TD>26</TD><TD>27</TD><TD>28</TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD></TR>
1
<TR ALIGN=RIGHT><TD>29</TD><TD>30</TD><TD>31</TD><TD>32</TD><TD>33</TD><TD>34</TD><TD>35</TD><TD>36</TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD></TR>
2 3
<TR ALIGN=RIGHT><TD>37</TD><TD>38</TD><TD>39</TD><TD>40</TD><TD>41</TD><TD>42</TD><TD>43</TD><TD>44</TD><TD>45</TD><TD></TD><TD></TD><TD></TD><TD></TD><TD></TD></TR>
4 5 6
<TR ALIGN=RIGHT><TD>46</TD><TD>47</TD><TD>48</TD><TD>49</TD><TD>50</TD><TD>51</TD><TD>52</TD><TD>53</TD><TD>54</TD><TD>55</TD><TD></TD><TD></TD><TD></TD><TD></TD></TR>
7 8 9 10
<TR ALIGN=RIGHT><TD>56</TD><TD>57</TD><TD>58</TD><TD>59</TD><TD>60</TD><TD>61</TD><TD>62</TD><TD>63</TD><TD>64</TD><TD>65</TD><TD>66</TD><TD></TD><TD></TD><TD></TD></TR>
11 12 13 14 15
<TR ALIGN=RIGHT><TD>67</TD><TD>68</TD><TD>69</TD><TD>70</TD><TD>71</TD><TD>72</TD><TD>73</TD><TD>74</TD><TD>75</TD><TD>76</TD><TD>77</TD><TD>78</TD><TD></TD><TD></TD></TR>
16 17 18 19 20 21
<TR ALIGN=RIGHT><TD>79</TD><TD>80</TD><TD>81</TD><TD>82</TD><TD>83</TD><TD>84</TD><TD>85</TD><TD>86</TD><TD>87</TD><TD>88</TD><TD>89</TD><TD>90</TD><TD>91</TD><TD></TD></TR>
22 23 24 25 26 27 28
<TR ALIGN=RIGHT><TD>92</TD><TD>93</TD><TD>94</TD><TD>95</TD><TD>96</TD><TD>97</TD><TD>98</TD><TD>99</TD><TD>100</TD><TD>101</TD><TD>102</TD><TD>103</TD><TD>104</TD><TD>105</TD>
29 30 31 32 33 34 35 36
</TABLE>
37 38 39 40 41 42 43 44 45
46 47 48 49 50 51 52 53 54 55
56 57 58 59 60 61 62 63 64 65 66
67 68 69 70 71 72 73 74 75 76 77 78
79 80 81 82 83 84 85 86 87 88 89 90 91
92 93 94 95 96 97 98 99 100 101 102 103 104 105 </pre>


=={{header|Scala}}==
=={{header|Scala}}==

Revision as of 22:16, 20 July 2016

Task
Floyd's triangle
You are encouraged to solve this task according to the task description, using any language you may know.

Floyd's triangle   lists the natural numbers in a right triangle aligned to the left where

  • the first row is just   1
  • successive rows start towards the left with the next number followed by successive naturals listing one more number than the line above.


The first few lines of a Floyd triangle looks like this:

 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15


Task
  1. Write a program to generate and display here the first   n   lines of a Floyd triangle.
    (Use   n=5   and   n=14   rows).
  2. Ensure that when displayed in a mono-space font, the numbers line up in vertical columns as shown and that only one space separates numbers of the last row.



Ada

<lang Ada>with Ada.Text_IO, Ada.Integer_Text_IO, Ada.Command_Line;

procedure Floyd_Triangle is

  Rows:    constant Positive := Integer'Value(Ada.Command_Line.Argument(1));
  Current:          Positive := 1;
  Width:            array(1 .. Rows) of Positive;

begin

  -- compute the width for the different columns
  for I in Width'Range loop
     Width(I) := Integer'Image(I + (Rows * (Rows-1))/2)'Length;
  end loop;
  
  -- output the triangle
  for Line in 1 .. Rows loop
     for Column in 1 .. Line loop
       Ada.Integer_Text_IO.Put(Current, Width => Width(Column));
       Current := Current + 1;
     end loop;
     Ada.Text_IO.New_Line;
  end loop;

end Floyd_Triangle;</lang>

Output:
> ./floyd_triangle 5
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15


> ./floyd_triangle 14
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
 16 17 18 19 20 21
 22 23 24 25 26 27 28
 29 30 31 32 33 34 35 36
 37 38 39 40 41 42 43 44  45
 46 47 48 49 50 51 52 53  54  55
 56 57 58 59 60 61 62 63  64  65  66
 67 68 69 70 71 72 73 74  75  76  77  78
 79 80 81 82 83 84 85 86  87  88  89  90  91
 92 93 94 95 96 97 98 99 100 101 102 103 104 105

ALGOL 68

Works with: ALGOL 68G version Any - tested with release 2.8.win32

<lang algol68># procedure to print a Floyd's Triangle with n lines # PROC floyds triangle = ( INT n )VOID: BEGIN

   # calculate the number of the highest number that will be printed     #
   # ( the sum of the integers 1, 2, ... n )                             #
   INT max number = ( n * ( n + 1 ) ) OVER 2;
   # determine the widths required to print the numbers of the final row #
   [ n ]INT widths;
   INT number := max number + 1;
   FOR col FROM n BY -1 TO 1 DO
       widths[ col ] := - ( UPB whole( number -:= 1, 0 ) + 1 )
   OD;
   # print the triangle                                                  #
   INT element := 0;
   FOR row TO n DO
       FOR col TO row DO
           print( ( whole( element +:= 1, widths[ col ] ) ) )
       OD;
       print( ( newline ) )
   OD

END; # floyds triangle #

main: (

   floyds triangle(  5 );
   print( ( newline ) );
   floyds triangle( 14 )

)</lang>

Output:
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15

  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
 16 17 18 19 20 21
 22 23 24 25 26 27 28
 29 30 31 32 33 34 35 36
 37 38 39 40 41 42 43 44  45
 46 47 48 49 50 51 52 53  54  55
 56 57 58 59 60 61 62 63  64  65  66
 67 68 69 70 71 72 73 74  75  76  77  78
 79 80 81 82 83 84 85 86  87  88  89  90  91
 92 93 94 95 96 97 98 99 100 101 102 103 104 105

AutoHotkey

<lang AutoHotkey>Floyds_triangle(row){ i = 0 loop %row% { n := A_Index loop, %n% { m := n, j := i, i++ while (m<row) j += m , m++ res .= spaces(StrLen(j+1)-StrLen(i) +(A_Index=1?0:1)) i } if (A_Index < row) res .= "`r`n" } return res } Spaces(no){ loop, % no res.=" " return % res }</lang> Examples:<lang AutoHotkey>MsgBox % Floyds_triangle(14)</lang>

Outputs:

 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35 36
37 38 39 40 41 42 43 44  45
46 47 48 49 50 51 52 53  54  55
56 57 58 59 60 61 62 63  64  65  66
67 68 69 70 71 72 73 74  75  76  77  78
79 80 81 82 83 84 85 86  87  88  89  90  91
92 93 94 95 96 97 98 99 100 101 102 103 104 105

AWK

<lang AWK>#!/bin/awk -f

BEGIN { if (rows !~ /^[0-9]+$/ || rows < 0) { print "invalid rows or missing from command line" print "syntax: awk -v rows=14 -f floyds_triangle.awk" exit 1 }

for (row=cols=1; row<=rows; row++ cols++) { width[row] = length(row + (rows * (rows-1))/2) for (col=1; col<=cols; col++) printf("%*d%c", width[col], ++n, row == col ? "\n" : " ") } } </lang>

output from: awk -f floyds_triangle.awk -v rows=5

 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15

output from: awk -f floyds_triangle.awk -v rows=14

 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35 36
37 38 39 40 41 42 43 44  45
46 47 48 49 50 51 52 53  54  55
56 57 58 59 60 61 62 63  64  65  66
67 68 69 70 71 72 73 74  75  76  77  78
79 80 81 82 83 84 85 86  87  88  89  90  91
92 93 94 95 96 97 98 99 100 101 102 103 104 105

BBC BASIC

<lang bbcbasic> n = 14

     num = 1
     last = (n^2 - n + 2) DIV 2
     FOR row = 1 TO n
       col = last
       FOR num = num TO num + row - 1
         @% = LEN(STR$(col)) + 1 : REM set column width
         PRINT num ;
         col += 1
       NEXT
       PRINT
     NEXT row</lang>

Output for n = 5:

  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15

Output for n = 14:

  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
 16 17 18 19 20 21
 22 23 24 25 26 27 28
 29 30 31 32 33 34 35 36
 37 38 39 40 41 42 43 44  45
 46 47 48 49 50 51 52 53  54  55
 56 57 58 59 60 61 62 63  64  65  66
 67 68 69 70 71 72 73 74  75  76  77  78
 79 80 81 82 83 84 85 86  87  88  89  90  91
 92 93 94 95 96 97 98 99 100 101 102 103 104 105

Befunge

This example is incomplete. The numbers in the tree aren't correctly aligned. Please ensure that it meets all task requirements and remove this message.

<lang Befunge>0" :swor fo rebmuN">:#,_&>55v >1+\1-:#v_$$1+\1- 55+,:v>$$@+ ^,*84.:\<+1\+1/2*+1:::\_^#:,<</lang>

Output:
Number of rows: 5

1  
2  3  
4  5  6  
7  8  9  10  
11  12  13  14  15  

Bracmat

<lang bracmat> ( ( floyd

   =   lowerLeftCorner lastInColumn lastInRow row i W w
     .   put$(str$("Floyd " !arg ":\n"))
       &   !arg*(!arg+-1)*1/2+1
         : ?lowerLeftCorner
         : ?lastInColumn
       & 1:?lastInRow:?row:?i
       &   whl
         ' ( !row:~>!arg
           & @(!lastInColumn:? [?W)
           & @(!i:? [?w)
           & whl'(!w+1:~>!W:?w&put$" ")
           & put$!i
           & (   !i:<!lastInRow
               & put$" "
               & 1+!lastInColumn:?lastInColumn
             |   put$\n
               & (1+!row:?row)+!lastInRow:?lastInRow
               & !lowerLeftCorner:?lastInColumn
             )
           & 1+!i:?i
           )
   )
 & floyd$5
 & floyd$14
 );</lang>

Output:

Floyd 5:
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
Floyd 14:
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35 36
37 38 39 40 41 42 43 44  45
46 47 48 49 50 51 52 53  54  55
56 57 58 59 60 61 62 63  64  65  66
67 68 69 70 71 72 73 74  75  76  77  78
79 80 81 82 83 84 85 86  87  88  89  90  91
92 93 94 95 96 97 98 99 100 101 102 103 104 105

C

<lang c>#include <stdio.h>

void t(int n) { int i, j, c, len;

i = n * (n - 1) / 2; for (len = c = 1; c < i; c *= 10, len++); c -= i; // c is the col where width changes

  1. define SPEED_MATTERS 0
  2. if SPEED_MATTERS // in case we really, really wanted to print huge triangles often

char tmp[32], s[4096], *p;

sprintf(tmp, "%*d", len, 0);

inline void inc_numstr(void) { int k = len;

redo: if (!k--) return;

if (tmp[k] == '9') { tmp[k] = '0'; goto redo; }

if (++tmp[k] == '!') tmp[k] = '1'; }

for (p = s, i = 1; i <= n; i++) { for (j = 1; j <= i; j++) { inc_numstr(); __builtin_memcpy(p, tmp + 1 - (j >= c), len - (j < c)); p += len - (j < c);

*(p++) = (i - j)? ' ' : '\n';

if (p - s + len >= 4096) { fwrite(s, 1, p - s, stdout); p = s; } } }

fwrite(s, 1, p - s, stdout);

  1. else // NO_IT_DOESN'T

int num; for (num = i = 1; i <= n; i++) for (j = 1; j <= i; j++) printf("%*d%c", len - (j < c), num++, i - j ? ' ':'\n');

  1. endif

}

int main(void) { t(5), t(14);

// maybe not // t(10000); return 0; }</lang> Output identical to D's.

C++

<lang cpp>

  1. include <windows.h>
  2. include <sstream>
  3. include <iostream>

//-------------------------------------------------------------------------------------------------- using namespace std;

//-------------------------------------------------------------------------------------------------- class floyds_tri { public:

   floyds_tri()  { lastLineLen = 0; }
   ~floyds_tri() { killArray(); }
   void create( int rows )
   {

_rows = rows; calculateLastLineLen(); display();

   }

private:

   void killArray()
   {

if( lastLineLen ) delete [] lastLineLen;

   }
   void calculateLastLineLen()
   {

killArray(); lastLineLen = new BYTE[_rows];

int s = 1 + ( _rows * ( _rows - 1 ) ) / 2;

for( int x = s, ix = 0; x < s + _rows; x++, ix++ ) { ostringstream cvr; cvr << x; lastLineLen[ix] = static_cast<BYTE>( cvr.str().size() ); }

   }
   void display()
   {

cout << endl << "Floyd\'s Triangle - " << _rows << " rows" << endl << "===============================================" << endl; int number = 1; for( int r = 0; r < _rows; r++ ) { for( int c = 0; c <= r; c++ ) { ostringstream cvr; cvr << number++; string str = cvr.str(); while( str.length() < lastLineLen[c] ) str = " " + str; cout << str << " "; } cout << endl; }

   }
   int _rows;
   BYTE* lastLineLen;

}; //-------------------------------------------------------------------------------------------------- int main( int argc, char* argv[] ) {

   floyds_tri t;
   int s;
   while( true )
   {

cout << "Enter the size of the triangle ( 0 to QUIT ): "; cin >> s; if( !s ) return 0; if( s > 0 ) t.create( s );

cout << endl << endl; system( "pause" );

   }
   return 0;

} //--------------------------------------------------------------------------------------------------</lang>

Output:
Floyd's Triangle - 5 rows
===============================================
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15


Floyd's Triangle - 14 rows
===============================================
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35 36
37 38 39 40 41 42 43 44  45
46 47 48 49 50 51 52 53  54  55
56 57 58 59 60 61 62 63  64  65  66
67 68 69 70 71 72 73 74  75  76  77  78
79 80 81 82 83 84 85 86  87  88  89  90  91
92 93 94 95 96 97 98 99 100 101 102 103 104 105

C#

Translation of: Perl

<lang csharp>using System; using System.Text;

public class FloydsTriangle {

   internal static void Main(string[] args)
   {
       int count;
       if (args.Length >= 1 && int.TryParse(args[0], out count) && count > 0)
       {
           Console.WriteLine(MakeTriangle(count));
       }
       else
       {
           Console.WriteLine(MakeTriangle(5));
           Console.WriteLine();
           Console.WriteLine(MakeTriangle(14));
       }
   }
   public static string MakeTriangle(int rows)
   {
       int maxValue = (rows * (rows + 1)) / 2;
       int digit = 0;
       StringBuilder output = new StringBuilder();
       for (int row = 1; row <= rows; row++)
       {
           for (int column = 0; column < row; column++)
           {
               int colMaxDigit = (maxValue - rows) + column + 1;
               if (column > 0)
               {
                   output.Append(' ');
               }
               digit++;
               output.Append(digit.ToString().PadLeft(colMaxDigit.ToString().Length));
           }
           output.AppendLine();
       }
       return output.ToString();
   }

}</lang>

CoffeeScript

Translation of: Kotlin

<lang coffeescript>triangle = (array) -> for n in array

   console.log "#{n} rows:"
   printMe = 1
   printed = 0
   row = 1
   to_print = ""
   while row <= n
       cols = Math.ceil(Math.log10(n * (n - 1) / 2 + printed + 2.0))
       p = ("" + printMe).length
       while p++ <= cols
           to_print += ' '
       to_print += printMe + ' '
       if ++printed == row
           console.log to_print
           to_print = ""
           row++
           printed = 0
       printMe++

triangle [5, 14]</lang> Output as Kotlin.

Common Lisp

Version 1

<lang lisp>;;;using flet to define local functions and storing precalculated column widths in array

verbose, but more readable and efficient than version 2

(defun floydtriangle (rows)

      (let (column-widths)
        (setf column-widths (make-array rows :initial-element nil))
          (flet (
            (lazycat (n)
             (/ (+ (expt n 2) n 2) 2))
            (width (v)
             (+ 1 (floor (log v 10)))))
           (dotimes (i rows)
            (setf (aref column-widths i)(width (+ i (lazycat (- rows 1))))))
           (dotimes (row rows)
            (dotimes (col (+ 1 row))
              (format t "~vd " (aref column-widths col)(+ col (lazycat row))))
            (format t "~%")))))</lang>

Version 2 - any base

<lang lisp>;;; more concise than version 1 but less efficient for a large triangle

optional "base" parameter will allow use of any base from 2 to 36

(defun floydtriangle (rows &optional (base 10))

      (dotimes (row rows)
        (dotimes (column (+ 1 row))
          (format t "~v,vr " base (length (format nil "~vr" base (+ column (/ (+ (expt (- rows 1) 2) (- rows 1) 2) 2)))) (+ column (/ (+ (expt row 2) row 2) 2))))
        (format t "~%")))</lang>
Output:
(floydtriangle 5)
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15

(floydtriangle 14)
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35 36
37 38 39 40 41 42 43 44  45
46 47 48 49 50 51 52 53  54  55
56 57 58 59 60 61 62 63  64  65  66
67 68 69 70 71 72 73 74  75  76  77  78
79 80 81 82 83 84 85 86  87  88  89  90  91
92 93 94 95 96 97 98 99 100 101 102 103 104 105

(floydtriangle 5 2)
   1 
  10   11 
 100  101  110 
 111 1000 1001 1010 
1011 1100 1101 1110 1111 

(floydtriangle 14 36)
 1 
 2  3 
 4  5  6 
 7  8  9  A 
 B  C  D  E  F 
 G  H  I  J  K  L 
 M  N  O  P  Q  R  S 
 T  U  V  W  X  Y  Z 10 
11 12 13 14 15 16 17 18 19 
1A 1B 1C 1D 1E 1F 1G 1H 1I 1J 
1K 1L 1M 1N 1O 1P 1Q 1R 1S 1T 1U 
1V 1W 1X 1Y 1Z 20 21 22 23 24 25 26 
27 28 29 2A 2B 2C 2D 2E 2F 2G 2H 2I 2J 
2K 2L 2M 2N 2O 2P 2Q 2R 2S 2T 2U 2V 2W 2X

D

<lang d>import std.stdio, std.conv;

void floydTriangle(in uint n) {

   immutable lowerLeftCorner = n * (n - 1) / 2 + 1;
   foreach (r; 0 .. n)
       foreach (c; 0 .. r + 1)
           writef("%*d%c",
                  text(lowerLeftCorner + c).length,
                  r * (r + 1) / 2 + c + 1,
                  c == r ? '\n' : ' ');

}

void main() {

   floydTriangle(5);
   floydTriangle(14);

}</lang>

Output:
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35 36
37 38 39 40 41 42 43 44  45
46 47 48 49 50 51 52 53  54  55
56 57 58 59 60 61 62 63  64  65  66
67 68 69 70 71 72 73 74  75  76  77  78
79 80 81 82 83 84 85 86  87  88  89  90  91
92 93 94 95 96 97 98 99 100 101 102 103 104 105

Elixir

<lang elixir>defmodule Floyd do

 def triangle(n) do
   max = trunc(n * (n + 1) / 2)
   widths = for m <- (max - n + 1)..max, do: (m |> Integer.to_string |> String.length) + 1
   format = Enum.map(widths, fn wide -> "~#{wide}w" end) |> List.to_tuple
   line(n, 0, 1, format)
 end
 
 def line(n, n, _, _), do: :ok
 def line(n, i, count, format) do
   Enum.each(0..i, fn j -> :io.fwrite(elem(format,j), [count+j]) end)
   IO.puts ""
   line(n, i+1, count+i+1, format)
 end

end

Floyd.triangle(5) Floyd.triangle(14)</lang>

Output:
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
 16 17 18 19 20 21
 22 23 24 25 26 27 28
 29 30 31 32 33 34 35 36
 37 38 39 40 41 42 43 44  45
 46 47 48 49 50 51 52 53  54  55
 56 57 58 59 60 61 62 63  64  65  66
 67 68 69 70 71 72 73 74  75  76  77  78
 79 80 81 82 83 84 85 86  87  88  89  90  91
 92 93 94 95 96 97 98 99 100 101 102 103 104 105

Erlang

<lang erlang> -module( floyds_triangle ).

-export( [integers/1, print/1, strings/1, task/0] ).

integers( N ) ->

         lists:reverse( integers_reversed(N) ).

print( N ) ->

      [io:fwrite("~s~n", [lists:flatten(X)]) || X <- strings(N)].

strings( N ) ->

       Strings_reversed = [strings_from_integers(X) || X <- integers_reversed(N)],
       Paddings = paddings( [lengths(X) || X <- Strings_reversed] ),
       [formats(X, Y) || {X, Y} <- lists:zip(Paddings, lists:reverse(Strings_reversed))].

task() ->

      print( 5	),
      print( 14 ).


formats( Paddings, Strings ) -> [lists:flatten(io_lib:format(" ~*s", [X, Y])) || {X, Y} <- lists:zip(Paddings, Strings)].

integers_reversed( N ) ->

         {_End, Integers_reversed} = lists:foldl( fun integers_reversed/2, {1, []}, lists:seq(0, N - 1) ),
         Integers_reversed.

integers_reversed( N, {Start, Acc} ) ->

         End = Start + N,
         {End + 1, [lists:seq(Start, End) | Acc]}.

lengths( Strings ) -> [string:len(X) || X <- Strings].

paddings( [Last_line | T] ) ->

         {[], Paddings} = lists:foldl( fun paddings/2, {paddings_lose_last(Last_line), [Last_line]}, lists:seq(1, erlang:length(T)) ),
         Paddings.

paddings( _N, {Current, Acc} ) -> {paddings_lose_last(Current), [Current | Acc]}.

paddings_lose_last( List ) -> [_H | T] = lists:reverse( List ), lists:reverse( T ).

strings_from_integers( Integers ) -> [erlang:integer_to_list(X) || X <- Integers]. </lang>

Output:
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
 16 17 18 19 20 21
 22 23 24 25 26 27 28
 29 30 31 32 33 34 35 36
 37 38 39 40 41 42 43 44  45
 46 47 48 49 50 51 52 53  54  55
 56 57 58 59 60 61 62 63  64  65  66
 67 68 69 70 71 72 73 74  75  76  77  78
 79 80 81 82 83 84 85 86  87  88  89  90  91
 92 93 94 95 96 97 98 99 100 101 102 103 104 105

ERRE

<lang ERRE> PROGRAM FLOYD

! ! for rosettacode.org !

BEGIN

 N=14
 NUM=1
 LAST=(N^2-N+2) DIV 2
 FOR ROW=1 TO N DO
   FOR J=1 TO ROW DO
      US$=STRING$(LEN(STR$(LAST-1+J))-1,"#")
      WRITE(US$;NUM;)
      PRINT(" ";)
      NUM+=1
   END FOR
   PRINT
 END FOR

END PROGRAM </lang> Example for n=14

Output:
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35 36
37 38 39 40 41 42 43 44  45
46 47 48 49 50 51 52 53  54  55
56 57 58 59 60 61 62 63  64  65  66
67 68 69 70 71 72 73 74  75  76  77  78
79 80 81 82 83 84 85 86  87  88  89  90  91
92 93 94 95 96 97 98 99 100 101 102 103 104 105

F#

<lang fsharp>open System

[<EntryPoint>] let main argv =

   // columns and rows are 0-based, so the input has to be decremented:
   let maxRow =
       match UInt32.TryParse(argv.[0]) with
       | (true, v) when v > 0u -> int (v - 1u)
       | (_, _) -> failwith "not a positive integer"
   let len (n: int) = int (Math.Floor(Math.Log10(float n)))
   let col0 row = row * (row + 1) / 2 + 1
   let col0maxRow = col0 maxRow
   for row in [0 .. maxRow] do
       for col in [0 .. row] do
           let value = (col0 row) + col
           let pad = String(' ', (len (col0maxRow + col) - len (value) + 1))
           printf "%s%d" pad value
       printfn ""
   0</lang>

Output for 5 and 14 (via command line argument)

  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
 16 17 18 19 20 21
 22 23 24 25 26 27 28
 29 30 31 32 33 34 35 36
 37 38 39 40 41 42 43 44  45
 46 47 48 49 50 51 52 53  54  55
 56 57 58 59 60 61 62 63  64  65  66
 67 68 69 70 71 72 73 74  75  76  77  78
 79 80 81 82 83 84 85 86  87  88  89  90  91
 92 93 94 95 96 97 98 99 100 101 102 103 104 105

Forth

<lang forth>: lastn ( rows -- n ) dup 1- * 2/ ;

width ( n -- n ) s>f flog ftrunc f>s 2 + ;
triangle ( rows -- )
 dup lastn 0 rot ( last 0 rows )
 0 do
   over cr
   i 1+ 0 do
     1+ swap 1+ swap
     2dup width u.r
   loop
   drop
 loop
 2drop ;

</lang>

Fortran

Please find compilation instructions on GNU/linux system at the beginning of the source. There, also, are the example output triangles produced by running the program. The environment variable setting and command line argument are vestigial. Ignore them. The code demonstrates writing to an in memory buffer, an old feature of FORTRAN. <lang FORTRAN> !-*- mode: compilation; default-directory: "/tmp/" -*- !Compilation started at Tue May 21 22:55:08 ! !a=./f && make $a && OMP_NUM_THREADS=2 $a 1223334444 !gfortran -std=f2008 -Wall -ffree-form -fall-intrinsics f.f08 -o f ! 1 ! 2 3 ! 4 5 6 ! 7 8 9 10 ! 11 12 13 14 15 ! ! ! 1 ! 2 3 ! 4 5 6 ! 7 8 9 10 ! 11 12 13 14 15 ! 16 17 18 19 20 21 ! 22 23 24 25 26 27 28 ! 29 30 31 32 33 34 35 36 ! 37 38 39 40 41 42 43 44 45 ! 46 47 48 49 50 51 52 53 54 55 ! 56 57 58 59 60 61 62 63 64 65 66 ! 67 68 69 70 71 72 73 74 75 76 77 78 ! 79 80 81 82 83 84 85 86 87 88 89 90 91 ! 92 93 94 95 96 97 98 99 100 101 102 103 104 105 ! ! ! !Compilation finished at Tue May 21 22:55:08


program p

 integer, dimension(2) :: examples = [5, 14]
 integer :: i
 do i=1, size(examples)
   call floyd(examples(i))
   write(6, '(/)')
 end do

contains

 subroutine floyd(rows)
   integer, intent(in) :: rows
   integer :: n, i, j, k
   integer, dimension(60) :: L
   character(len=504) :: fmt
   n = (rows*(rows+1))/2 ! Gauss's formula
   do i=1,rows ! compute format of final row
     L(i) = 2+int(log10(real(n-rows+i)))
   end do
   k = 0
   do i=1,rows
     do j=1,i
       k = k+1
       write(fmt,'(a2,i1,a1)')'(i',L(j),')'
       write(6,fmt,advance='no') k
     enddo
     write(6,*) 
   end do
 end subroutine floyd
 

end program p </lang>

FreeBASIC

<lang freebasic>' version 19-09-2015 ' compile with: fbc -s console

Sub pascal_triangle(n As UInteger)

   Dim As UInteger a = 1, b, i, j, switch = n + 1
   Dim As String frmt, frmt_1, frmt_2
   ' last number of the last line
   i = (n * (n + 1)) \ 2
   frmt_2 = String(Len(Str(i)) + 1, "#")
   ' first number of the last line
   i = ((n - 1) * n) \ 2 + 1
   frmt_1 = String(Len(Str(i)) + 1, "#")
   ' we have 2 different formats strings
   ' find the point where we have to make the switch
   If frmt_1 <> frmt_2 Then
       j = i + 1
       While Len(Str(i)) = Len(Str(J))
           j =  j + 1
       Wend
       switch = j - i
   End If
   Print "output for "; Str(n) : Print
   For i = 1 To n
       frmt = frmt_1
       b = (i * (i + 1)) \ 2
       For j = a To b
           ' if we have the switching point change format string
           If j - a = switch Then frmt = frmt_2
           Print Using frmt; j;
       Next j
       Print
       a = b + 1
   Next i
   Print

End Sub

' ------=< MAIN >=------

pascal_triangle(5)

pascal_triangle(14)


' empty keyboard buffer While Inkey <> "" : Var _key_ = Inkey : Wend Print : Print "hit any key to end program" Sleep End</lang>

Output:
output for 5             output for 14  
                         
  1                        1
  2  3                     2  3
  4  5  6                  4  5  6
  7  8  9 10               7  8  9 10
 11 12 13 14 15           11 12 13 14 15
                          16 17 18 19 20 21
                          22 23 24 25 26 27 28
                          29 30 31 32 33 34 35 36
                          37 38 39 40 41 42 43 44  45
                          46 47 48 49 50 51 52 53  54  55
                          56 57 58 59 60 61 62 63  64  65  66
                          67 68 69 70 71 72 73 74  75  76  77  78
                          79 80 81 82 83 84 85 86  87  88  89  90  91
                          92 93 94 95 96 97 98 99 100 101 102 103 104 105

Go

<lang go>package main

import "fmt"

func main() {

   floyd(5)
   floyd(14)

}

func floyd(n int) {

   fmt.Printf("Floyd %d:\n", n)
   lowerLeftCorner := n*(n-1)/2 + 1
   lastInColumn := lowerLeftCorner
   lastInRow := 1
   for i, row := 1, 1; row <= n; i++ {
       w := len(fmt.Sprint(lastInColumn))
       if i < lastInRow {
           fmt.Printf("%*d ", w, i)
           lastInColumn++
       } else {
           fmt.Printf("%*d\n", w, i)
           row++
           lastInRow += row
           lastInColumn = lowerLeftCorner
       }
   }

}</lang>

Output:
Floyd 5:
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
Floyd 14:
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35 36
37 38 39 40 41 42 43 44  45
46 47 48 49 50 51 52 53  54  55
56 57 58 59 60 61 62 63  64  65  66
67 68 69 70 71 72 73 74  75  76  77  78
79 80 81 82 83 84 85 86  87  88  89  90  91
92 93 94 95 96 97 98 99 100 101 102 103 104 105

Haskell

Program <lang haskell>import Data.List import Control.Monad import Control.Arrow

alignR :: Int -> Integer -> String alignR n = (\s -> replicate (n - length s) ' ' ++ s). show

floydTriangle = liftM2 (zipWith (liftM2 (.) enumFromTo ((pred.). (+)))) (scanl (+) 1) id [1..]

formatFT n = mapM_ (putStrLn. unwords. zipWith alignR ws) t where

 t = take n floydTriangle
 ws = map (length. show) $ last t</lang>

Output: <lang haskell>*Main> formatFT 5

1
2  3
4  5  6
7  8  9 10

11 12 13 14 15

  • Main> formatFT 14
1
2  3
4  5  6
7  8  9 10

11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105</lang>

Icon and Unicon

The following solution works in both languages: <lang unicon>procedure main(a)

   n := integer(a[1]) | 5
   w := ((n*(n-1))/2)-n
   c := create seq()
   every row := 1 to n do {
       every col := 1 to row do {
           width := *(w+col)+1
           every writes(right(@c,width))
           }
       write()
       }

end</lang>

Sample outputs:

->ft
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
->
->ft 14
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
 16 17 18 19 20 21
 22 23 24 25 26 27 28
 29 30 31 32 33 34 35 36
 37 38 39 40 41 42 43 44  45
 46 47 48 49 50 51 52 53  54  55
 56 57 58 59 60 61 62 63  64  65  66
 67 68 69 70 71 72 73 74  75  76  77  78
 79 80 81 82 83 84 85 86  87  88  89  90  91
 92 93 94 95 96 97 98 99 100 101 102 103 104 105
->

J

Note: require 'strings' does nothing in J7, but is harmless (strings is already incorporated in J7).

<lang J>require 'strings' floyd=: [: rplc&(' 0';' ')"1@":@(* ($ $ +/\@,)) >:/~@:i.</lang>

Note, the parenthesis around ($ $ +/\@,) is optional, and only included for emphasis.

Example use:

<lang J> floyd 5

1            
2  3         
4  5  6      
7  8  9 10   

11 12 13 14 15

  floyd 14
1                                             
2  3                                          
4  5  6                                       
7  8  9 10                                    

11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105</lang>

How it works:

First, we create a square lower triangular matrix with our argument as the length of one side. We have 1s along the diagonal and the lower triangle, and 0s for the upper triangle.

Second, we create a running sum of these values (treating rows as being adjacent horizontally for this purpose). Then, we multiply this result by our lower triangular matrix (forcing the upper triangle to be 0s).

Then, we format the matrix as text (which gives us the required vertical alignment), and in each row we replace each space followed by a zero with two spaces.

Efficiency note: In a measurement of time used: in floyd 100, 80% the time here goes into the string manipulations -- sequential additions and multiplications are cheap. In floyd 1000 this jumps to 98% of the time. Here's a faster version (about 3x on floyd 1000) courtesy of Aai of the J forums:

<lang J>floyd=: [: ({.~ i.&1@E.~&' 0')"1@":@(* ($ $ +/\@,)) >:/~@:i.</lang>

Java

<lang java> public class Floyd { public static void main(String[] args){ printTriangle(5); printTriangle(14); }

private static void printTriangle(int n){ System.out.println(n + " rows:"); for(int rowNum = 1, printMe = 1, numsPrinted = 0; rowNum <= n; printMe++){ int cols = (int)Math.ceil(Math.log10(n*(n-1)/2 + numsPrinted + 2)); System.out.printf("%"+cols+"d ", printMe); if(++numsPrinted == rowNum){ System.out.println(); rowNum++; numsPrinted = 0; } } } }</lang> Output:

5 rows:
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 
14 rows:
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 
16 17 18 19 20 21 
22 23 24 25 26 27 28 
29 30 31 32 33 34 35 36 
37 38 39 40 41 42 43 44  45 
46 47 48 49 50 51 52 53  54  55 
56 57 58 59 60 61 62 63  64  65  66 
67 68 69 70 71 72 73 74  75  76  77  78 
79 80 81 82 83 84 85 86  87  88  89  90  91 
92 93 94 95 96 97 98 99 100 101 102 103 104 105 

JavaScript

ES 5

In a functional idiom of JavaScript.

Two main functions:

  1. an expression of the Floyd triangle as a list of lists (a function of the number of rows)
  2. a mapping of the expression to a formatted string.

<lang JavaScript>// Floyd triangles of 5 and 14 rows // right-aligned monospaced columns (nMargin allows for extra spacing) // () --> s function main() {

   // minimum space between numbers - adjust for visual preference
   var nMargin = 1;
   // Formatted strings for Floyd's triangles of 5 and 14 rows
   return (function (lstN) {
       return lstN.map(function (nFloydRows) {
           var lstRows = floydIntegerLists(nFloydRows),
               iLast = nFloydRows - 1;
           return colsSpacedRight(
               lstRows,
               // Minimum space required per number cell
               // nMargin more than the width of the final number
               lstRows[iLast][iLast].toString().length + nMargin
           )
       }).join('\n\n');
   })([5, 14]);

}

// n Floyd's triangle rows // n --> n function floydIntegerLists(nRows) {

   // Full integer list folded into list of rows
   // [n] --> n
   return (function triangleNumbers(lstInt, startWidth) {
       var n = startWidth || 1;
       return n > lstInt.length ? [] : [lstInt.slice(0, n)].concat(
           triangleNumbers(lstInt.slice(n), n + 1)
       )
   })(
       range(
           1,
           Math.floor(
               (nRows * nRows) / 2
           ) + Math.ceil(
               nRows / 2
           )
       )
   );

}

// list of list of numbers --> lines of fixed right-aligned col width // n --> s function colsSpacedRight(lstLines, nColWidth) {

   return lstLines.reduce(
       function (s, line) {
           return s + line.map(function (n) {
               return rightAligned(n, nColWidth)
           }).join() + '\n';
       }, 
   )

}

// range(1, 20) --> [1..20] function range(m, n) {

   return Array.apply(null, Array(n - m + 1)).map(
       function (x, i) {
           return m + i;
       }
   );

}

// Integer as right-padded string of given width // n --> n --> s function rightAligned(n, width) {

   var strN = n.toString();
   return Array(width - strN.length + 1).join(' ') + strN;

}

console.log( // if the context is a browser

   main()

);</lang>

Output:

  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15


   1
   2   3
   4   5   6
   7   8   9  10
  11  12  13  14  15
  16  17  18  19  20  21
  22  23  24  25  26  27  28
  29  30  31  32  33  34  35  36
  37  38  39  40  41  42  43  44  45
  46  47  48  49  50  51  52  53  54  55
  56  57  58  59  60  61  62  63  64  65  66
  67  68  69  70  71  72  73  74  75  76  77  78
  79  80  81  82  83  84  85  86  87  88  89  90  91
  92  93  94  95  96  97  98  99 100 101 102 103 104 105

Spidermonkey

(Used TCL example as a starting point.)

<lang javascript>#!/usr/bin/env js

function main() {

   print('Floyd 5:');
   floyd(5);
   print('\nFloyd 14:');
   floyd(14);

}


function padLeft(s, w) {

   for (s = String(s); s.length < w; s = ' ' + s);
   return s;

}


function floyd(nRows) {

   var lowerLeft = nRows * (nRows - 1) / 2 + 1;
   var lowerRight = nRows * (nRows + 1) / 2;
   
   var colWidths = [];
   for (var col = lowerLeft; col <= lowerRight; col++) {
       colWidths.push(String(col).length);
   }
   var  num = 1;
   for (var row = 0; row < nRows; row++) {
       var line = [];
       for (var col = 0; col <= row; col++, num++) {
           line.push(padLeft(num, colWidths[col]));
       }
       print(line.join(' '));
   }

}

main();</lang>

Output:
 Floyd 5:
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
 
 Floyd 14:
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
 16 17 18 19 20 21
 22 23 24 25 26 27 28
 29 30 31 32 33 34 35 36
 37 38 39 40 41 42 43 44  45
 46 47 48 49 50 51 52 53  54  55
 56 57 58 59 60 61 62 63  64  65  66
 67 68 69 70 71 72 73 74  75  76  77  78
 79 80 81 82 83 84 85 86  87  88  89  90  91
 92 93 94 95 96 97 98 99 100 101 102 103 104 105

jq

<lang jq># floyd(n) creates an n-row floyd's triangle def floyd(n):

 def lpad(len): tostring | (((len - length) * " ")  + .);
 # Construct an array of widths.
 # Assuming N is the last integer on the last row (i.e. (n+1)*n/2),
 # the last row has n entries from (1+N-n) through N:
 def widths:
   ((n+1)*n/2) as $N
   | [range(1 + $N - n; $N + 1) | tostring | length];
 # emit line k assuming it starts with the integer "start"
 def line(start; k; widths):
   reduce range(start; start+k) as $i
     (""; . + ($i|lpad(widths[$i - start])) + " ");
 widths as $widths
 | (reduce range(0;n) as $row
     ( [0, ""];   # state: i, string
       (.[0] + 1) as $i | .[1] as $string
       | [ ($i + $row),
           ($string + "\n" + line($i; $row + 1; $widths )) ] )
   | .[1] ) ;</lang>

Task: <lang jq>(5,14) | "floyd(\(.)): \(floyd(.))\n"</lang>

Output:

<lang sh>$ jq -M -r -n -f floyds_triangle.jq > floyds_triangle.out floyd(5):

1 
2  3 
4  5  6 
7  8  9 10 

11 12 13 14 15

floyd(14):

1 
2  3 
4  5  6 
7  8  9 10 

11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 </lang>

Julia

<lang julia>#floyd(n) creates an n-row floyd's triangle counting from 1 to (n/2+.5)*n function floyd(n) x = 1 dig(x,line,n) = (while line < n; x+=line; line+= 1 end; return ndigits(x)+1) for line = 1:n, i = 1:line; print(lpad(x,dig(x,line,n)," ")); x+=1; i==line && print("\n") end end</lang>

julia> floyd(5)
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15

julia> floyd(14)
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
 16 17 18 19 20 21
 22 23 24 25 26 27 28
 29 30 31 32 33 34 35 36
 37 38 39 40 41 42 43 44  45
 46 47 48 49 50 51 52 53  54  55
 56 57 58 59 60 61 62 63  64  65  66
 67 68 69 70 71 72 73 74  75  76  77  78
 79 80 81 82 83 84 85 86  87  88  89  90  91
 92 93 94 95 96 97 98 99 100 101 102 103 104 105

Here is another solution that makes use of the fact that the number in the (i,j)th position in the array is equal to the sum of j and the binomial coefficient (j,2). This number should be padded according to the number of digits in the coefficient (n,j). <lang julia>floyd(n) =

 pprint([join([lpad(j+binomial(i,2), (j==1?0:1)+ndigits(j+binomial(n,2)), " ") 
              for j=1:i]) 
        for i=1:n])

pprint(matrix) = for i = 1:size(matrix,1) println(join(matrix[i,:])) end </lang>

Output:
julia> floyd(5)
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15

Kotlin

Translation of: Java

<lang scala>fun main(args: Array<String>) = args.forEach { Triangle(it.toInt()) }

internal class Triangle(n: Int) {

   init {
       println("$n rows:")
       var printMe = 1
       var printed = 0
       var row = 1
       while (row <= n) {
           val cols = Math.ceil(Math.log10(n * (n - 1) / 2 + printed + 2.0)).toInt()
           print("%${cols}d ".format(printMe))
           if (++printed == row) { println(); row++; printed = 0 }
           printMe++
       }
   }

}</lang> Output as Java.

Lasso

This example does not show the output mentioned in the task description on this page (or a page linked to from here). There should only be one space between the numbers on the last row. Please ensure that it meets all task requirements and remove this message.
Note that phrases in task descriptions such as "print and display" and "print and show" for example, indicate that (reasonable length) output be a part of a language's solution.


<lang Lasso>define floyds_triangle(n::integer) => { local(out = array(array(1)),comp = array, num = 1) while(#out->size < #n) => { local(new = array) loop(#out->last->size + 1) => { #num++ #new->insert(#num) } #out->insert(#new) } local(pad = #out->last->last->asString->size) with line in #out do => { local(lineout = string) with i in #line do => { #i != #line->first ? #lineout->append(' ') #lineout->append((' '*(#pad - #i->asString->size))+#i) } #comp->insert(#lineout) } return #comp->join('\r') } floyds_triangle(5) '\r\r' floyds_triangle(14)</lang>

Output:
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15

  1
  2   3
  4   5   6
  7   8   9  10
 11  12  13  14  15
 16  17  18  19  20  21
 22  23  24  25  26  27  28
 29  30  31  32  33  34  35  36
 37  38  39  40  41  42  43  44  45
 46  47  48  49  50  51  52  53  54  55
 56  57  58  59  60  61  62  63  64  65  66
 67  68  69  70  71  72  73  74  75  76  77  78
 79  80  81  82  83  84  85  86  87  88  89  90  91
 92  93  94  95  96  97  98  99 100 101 102 103 104 105

Liberty BASIC

<lang lb>input "Number of rows needed:- "; rowsNeeded

dim colWidth(rowsNeeded) ' 5 rows implies 5 columns

for col=1 to rowsNeeded

   colWidth(col) = len(str$(col + rowsNeeded*(rowsNeeded-1)/2))

next

currentNumber =1

for row=1 to rowsNeeded

   for col=1 to row
       print right$( "  "+str$( currentNumber), colWidth(col)); " ";
       currentNumber = currentNumber + 1
   next
   print

next</lang>

Output:
Number of rows needed:- 5
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 

Number of rows needed:- 14
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 
16 17 18 19 20 21 
22 23 24 25 26 27 28 
29 30 31 32 33 34 35 36 
37 38 39 40 41 42 43 44  45 
46 47 48 49 50 51 52 53  54  55 
56 57 58 59 60 61 62 63  64  65  66 
67 68 69 70 71 72 73 74  75  76  77  78 
79 80 81 82 83 84 85 86  87  88  89  90  91 
92 93 94 95 96 97 98 99 100 101 102 103 104 105 

Lua

<lang lua>function print_floyd(rows) local c = 1 local h = rows*(rows-1)/2 for i=1,rows do local s = "" for j=1,i do for k=1, #tostring(h+j)-#tostring(c) do s = s .. " " end if j ~= 1 then s = s .. " " end s = s .. tostring(c) c = c + 1 end print(s) end end

print_floyd(5) print_floyd(14)</lang>

Output:

 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35 36
37 38 39 40 41 42 43 44  45
46 47 48 49 50 51 52 53  54  55
56 57 58 59 60 61 62 63  64  65  66
67 68 69 70 71 72 73 74  75  76  77  78
79 80 81 82 83 84 85 86  87  88  89  90  91
92 93 94 95 96 97 98 99 100 101 102 103 104 105

Mathematica / Wolfram Language

<lang Mathematica> f=Function[n, Most/@(Range@@@Partition[FindSequenceFunction[{1,2,4,7,11}]/@Range[n+1],2,1])] TableForm[f@5,TableAlignments->Right,TableSpacing->{1,1}] TableForm[f@14,TableAlignments->Right,TableSpacing->{1,1}] </lang> Output:

  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15

  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
 16 17 18 19 20 21
 22 23 24 25 26 27 28
 29 30 31 32 33 34 35 36
 37 38 39 40 41 42 43 44  45
 46 47 48 49 50 51 52 53  54  55
 56 57 58 59 60 61 62 63  64  65  66
 67 68 69 70 71 72 73 74  75  76  77  78
 79 80 81 82 83 84 85 86  87  88  89  90  91
 92 93 94 95 96 97 98 99 100 101 102 103 104 105

MATLAB / Octave

<lang Matlab>function floyds_triangle(n)

width = 1+floor(log10(nr*(nr+1)/2)); for k=1:n, fprintf(stdout,' %*i',[width(ones(1,k));k*(k-1)/2+1:k*(k+1)/2]);

       fprintf(stdout,'\n');

end;</lang> gives the output:

octave:22> floyds_triangle(5)
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15

NetRexx

Both REXX versions lend themselves very well to conversion into NetRexx programs with few changes.

Version 1

Translation of: REXX

<lang NetRexx>/* NetRexx */ options replace format comments java crossref symbols binary /* REXX ***************************************************************

  • 12.07.2012 Walter Pachl - translated from Python
                                                                                                                                            • /

Parse Arg rowcount . if rowcount.length() == 0 then rowcount = 1 say 'Rows:' rowcount say col = 0 len = Rexx ll = -- last line of triangle Loop j = rowcount * (rowcount - 1) / 2 + 1 to rowcount * (rowcount + 1) / 2

 col = col + 1                       -- column number
 ll = ll j                           -- build last line
 len[col] = j.length()               -- remember length of column
 End j

Loop i = 1 To rowcount - 1 -- now do and output the rest

 ol = 
 col = 0
 Loop j = i * (i - 1) / 2 + 1 to i * (i + 1) / 2 -- elements of line i
   col = col + 1
   ol=ol j.right(len[col])           -- element in proper length
   end
 Say ol                              -- output ith line
 end i

Say ll -- output last line </lang> Output:

Rows: 5 
 
  1 
  2  3 
  4  5  6 
  7  8  9 10 
 11 12 13 14 15 

Rows: 14 
 
  1 
  2  3 
  4  5  6 
  7  8  9 10 
 11 12 13 14 15 
 16 17 18 19 20 21 
 22 23 24 25 26 27 28 
 29 30 31 32 33 34 35 36 
 37 38 39 40 41 42 43 44  45 
 46 47 48 49 50 51 52 53  54  55 
 56 57 58 59 60 61 62 63  64  65  66 
 67 68 69 70 71 72 73 74  75  76  77  78 
 79 80 81 82 83 84 85 86  87  88  89  90  91 
 92 93 94 95 96 97 98 99 100 101 102 103 104 105 

Version 2

Translation of: REXX

<lang NetRexx>/* NetRexx */ options replace format comments java crossref symbols binary /*REXX program constructs & displays Floyd's triangle for any number of rows.*/ parse arg numRows . if numRows == then numRows = 1 -- assume 1 row if not given maxVal = numRows * (numRows + 1) % 2 -- calculate the max value. say 'displaying a' numRows "row Floyd's triangle:" say digit = 1 loop row = 1 for numRows

 col = 0
 output = 
 loop digit = digit for row
   col = col + 1
   colMaxDigit = maxVal - numRows + col
   output = output Rexx(digit).right(colMaxDigit.length())
   end digit
 say output
 end row

</lang>

Output:

displaying a 5 row Floyd's triangle: 
 
  1 
  2  3 
  4  5  6 
  7  8  9 10 
 11 12 13 14 15
  
displaying a 14 row Floyd's triangle: 
 
  1 
  2  3 
  4  5  6 
  7  8  9 10 
 11 12 13 14 15 
 16 17 18 19 20 21 
 22 23 24 25 26 27 28 
 29 30 31 32 33 34 35 36 
 37 38 39 40 41 42 43 44  45 
 46 47 48 49 50 51 52 53  54  55 
 56 57 58 59 60 61 62 63  64  65  66 
 67 68 69 70 71 72 73 74  75  76  77  78 
 79 80 81 82 83 84 85 86  87  88  89  90  91 
 92 93 94 95 96 97 98 99 100 101 102 103 104 105

Nim

Translation of: Python

<lang nim>import strutils

proc floyd(rowcount = 5): seq[seq[int]] =

 result = @[@[1]]
 while result.len < rowcount:
   let n = result[result.high][result.high] + 1
   var row = newSeq[int]()
   for i in n .. n + result[result.high].len:
     row.add i
   result.add row

proc pfloyd(rows) =

 var colspace = newSeq[int]()
 for n in rows[rows.high]: colspace.add(($n).len)
 for row in rows:
   for i, x in row:
     stdout.write align($x, colspace[i])," "
   echo ""

echo floyd()

for i in [5, 14]:

 pfloyd(floyd(i))
 echo ""</lang>

Output:

@[@[1], @[2, 3], @[4, 5, 6], @[7, 8, 9, 10], @[11, 12, 13, 14, 15]]
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 

 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 
16 17 18 19 20 21 
22 23 24 25 26 27 28 
29 30 31 32 33 34 35 36 
37 38 39 40 41 42 43 44  45 
46 47 48 49 50 51 52 53  54  55 
56 57 58 59 60 61 62 63  64  65  66 
67 68 69 70 71 72 73 74  75  76  77  78 
79 80 81 82 83 84 85 86  87  88  89  90  91 
92 93 94 95 96 97 98 99 100 101 102 103 104 105 

OCaml

<lang ocaml>let ( |> ) f g x = g (f x) let rec last = function x::[] -> x | _::tl -> last tl | [] -> raise Not_found let rec list_map2 f l1 l2 =

 match (l1, l2) with
 | ([], _) | (_, []) -> []
 | (x::xs, y::ys) -> (f x y) :: list_map2 f xs ys

let floyd n =

 let rec aux acc cur len i j =
   if (List.length acc) = n then (List.rev acc) else
     if j = len
     then aux ((List.rev cur)::acc) [] (succ len) i 0
     else aux acc (i::cur) len (succ i) (succ j)
 in
 aux [] [] 1 1 0

let print_floyd f =

 let lens = List.map (string_of_int |> String.length) (last f) in
 List.iter (fun row ->
   print_endline (
     String.concat " " (
       list_map2 (Printf.sprintf "%*d") lens row))
 ) f

let () =

 print_floyd (floyd (int_of_string Sys.argv.(1)))</lang>

OxygenBasic

This example does not show the output mentioned in the task description on this page (or a page linked to from here). Please ensure that it meets all task requirements and remove this message.
Note that phrases in task descriptions such as "print and display" and "print and show" for example, indicate that (reasonable length) output be a part of a language's solution.


<lang oxygenbasic> function Floyd(sys n) as string sys i,t for i=1 to n

 t+=i

next string s=str t sys le=1+len s string cr=chr(13,10) sys lc=len cr string buf=space(le*t+n*lc) sys j,o,p=1 t=0 for i=1 to n

 for j=1 to i
   t++
   s=str t
   o=le-len(s)-1 'right justify
   mid buf,p+o,str t
   p+=le
 next
 mid buf,p,cr
 p+=lc

next return left buf,p-1 end function

putfile "s.txt",Floyd(5)+floyd(14) </lang>

PARI/GP

This example is incorrect. Please fix the code and remove this message.

Details: It does not ensure that there is exactly one space between the columns in the last row.

<lang parigp>F(n)=my(fmt=Str("%"1+#Str(n*(n+1)/2)"d"),t);for(i=1,n,for(j=1,i,printf(fmt,t++));print) F(5) F(14)</lang>

Output:
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
   1
   2   3
   4   5   6
   7   8   9  10
  11  12  13  14  15
  16  17  18  19  20  21
  22  23  24  25  26  27  28
  29  30  31  32  33  34  35  36
  37  38  39  40  41  42  43  44  45
  46  47  48  49  50  51  52  53  54  55
  56  57  58  59  60  61  62  63  64  65  66
  67  68  69  70  71  72  73  74  75  76  77  78
  79  80  81  82  83  84  85  86  87  88  89  90  91
  92  93  94  95  96  97  98  99 100 101 102 103 104 105

Pascal

Works with: Free_Pascal

<lang pascal>Program FloydDemo (input, output);

function digits(number: integer): integer;

 begin
   digits := trunc(ln(number) / ln(10)) + 1;
 end;

procedure floyd1 (numberOfLines: integer); { variant with repeat .. until loop }

 var
   i, j, numbersInLine, startOfLastlLine: integer;

 begin
   startOfLastlLine := (numberOfLines - 1) * numberOfLines div 2 + 1;
   i := 1;
   j := 1;
   numbersInLine := 1;
   repeat
     repeat
       write(i: digits(startOfLastlLine - 1 + j), ' ');
       inc(i);

inc(j);

     until (j > numbersInLine);
     writeln;
     j := 1;
     inc(numbersInLine);
   until (numbersInLine > numberOfLines);
 end;

procedure floyd2 (numberOfLines: integer); { Variant with for .. do loop }

 var
   i, j, numbersInLine, startOfLastlLine: integer;

 begin
   startOfLastlLine := (numberOfLines - 1) * numberOfLines div 2 + 1;
   i := 1;
   for numbersInLine := 1 to numberOfLines do
   begin
     for j := 1 to numbersInLine do
     begin
       write(i: digits(startOfLastlLine - 1 + j), ' ');
       inc(i);
     end;
     writeln;
   end;
 end;

begin

 writeln ('*** Floyd 5 ***');
 floyd1(5);
 writeln;
 writeln ('*** Floyd 14 ***');
 floyd2(14);

end.</lang> Output:

% ./Floyd
*** Floyd 5 ***
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 

*** Floyd 14 ***
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 
16 17 18 19 20 21 
22 23 24 25 26 27 28 
29 30 31 32 33 34 35 36 
37 38 39 40 41 42 43 44  45 
46 47 48 49 50 51 52 53  54  55 
56 57 58 59 60 61 62 63  64  65  66 
67 68 69 70 71 72 73 74  75  76  77  78 
79 80 81 82 83 84 85 86  87  88  89  90  91 
92 93 94 95 96 97 98 99 100 101 102 103 104 105 

Perl

Translation of: NetRexx

<lang perl>#!/usr/bin/env perl use strict; use warnings;

sub displayFloydTriangle {

 my $numRows = shift;
 print "\ndisplaying a $numRows row Floyd's triangle:\n\n";
 my $maxVal = int($numRows * ($numRows + 1) / 2); # calculate the max value.
 my $digit = 0;
 foreach my $row (1 .. $numRows) {
   my $col = 0;
   my $output = ;
   foreach (1 .. $row) {
     ++$digit;
     ++$col;
     my $colMaxDigit = $maxVal - $numRows + $col;
     $output .= sprintf " %*d", length($colMaxDigit), $digit;
   }
   print "$output\n";
 }
 return;

}

  1. ==== Main ================================================

my @counts; @counts = @ARGV; @counts = (5, 14) unless @ARGV;

foreach my $count (@counts) {

 displayFloydTriangle($count);

}

0; __END__ </lang> Output:

displaying a 5 row Floyd's triangle:

  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15

displaying a 14 row Floyd's triangle:

  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
 16 17 18 19 20 21
 22 23 24 25 26 27 28
 29 30 31 32 33 34 35 36
 37 38 39 40 41 42 43 44  45
 46 47 48 49 50 51 52 53  54  55
 56 57 58 59 60 61 62 63  64  65  66
 67 68 69 70 71 72 73 74  75  76  77  78
 79 80 81 82 83 84 85 86  87  88  89  90  91
 92 93 94 95 96 97 98 99 100 101 102 103 104 105

Perl 6

Works with: rakudo version 2015-09-10

<lang perl6>constant @floyd = gather for 1..* -> $s { take [++$ xx $s] }

sub say-floyd($n) {

   my @formats = @floyd[$n-1].map: {"%{.chars}s"}
   for @floyd[^$n] -> @i {
       say ~(@i Z @formats).map: -> ($i, $f) { $i.fmt($f) }
   }

}

say-floyd 5; say-floyd 14;</lang>

Output:
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 
16 17 18 19 20 21 
22 23 24 25 26 27 28 
29 30 31 32 33 34 35 36 
37 38 39 40 41 42 43 44  45 
46 47 48 49 50 51 52 53  54  55 
56 57 58 59 60 61 62 63  64  65  66 
67 68 69 70 71 72 73 74  75  76  77  78 
79 80 81 82 83 84 85 86  87  88  89  90  91 
92 93 94 95 96 97 98 99 100 101 102 103 104 105

PHP

<lang php> <?php floyds_triangle(5); floyds_triangle(14);

function floyds_triangle($n) {

   echo "n = " . $n . "\r\n";
   for($r = 1, $i = 1, $c = 0; $r <= $n; $i++) {
       $cols = ceil(log10($n*($n-1)/2 + $c + 2));
       printf("%".$cols."d ", $i);
       if(++$c == $r) {
           echo "\r\n";
           $r++;
           $c = 0;
       }
   }

?> </lang>

Output:
 
n = 5
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 
n = 14
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 
16 17 18 19 20 21 
22 23 24 25 26 27 28 
29 30 31 32 33 34 35 36 
37 38 39 40 41 42 43 44  45 
46 47 48 49 50 51 52 53  54  55 
56 57 58 59 60 61 62 63  64  65  66 
67 68 69 70 71 72 73 74  75  76  77  78 
79 80 81 82 83 84 85 86  87  88  89  90  91 
92 93 94 95 96 97 98 99 100 101 102 103 104 105 

PicoLisp

Calculate widths relative to lower left corner

<lang PicoLisp>(de floyd (N)

  (let LLC (/ (* N (dec N)) 2)
     (for R N
        (for C R
           (prin
              (align
                 (length (+ LLC C))
                 (+ C (/ (* R (dec R)) 2)) ) )
           (if (= C R) (prinl) (space)) ) ) ) )</lang>

Pre-calculate all rows, and take format from last one

<lang PicoLisp>(de floyd (N)

  (let
     (Rows
        (make
           (for ((I . L) (range 1 (/ (* N (inc N)) 2))  L)
              (link (cut I 'L)) ) )
        Fmt (mapcar length (last Rows)) )
     (map inc (cdr Fmt))
     (for R Rows
        (apply tab R Fmt) ) ) )</lang>

Output in both cases:

: (floyd 5)
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15

: (floyd 14)
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35 36
37 38 39 40 41 42 43 44  45
46 47 48 49 50 51 52 53  54  55
56 57 58 59 60 61 62 63  64  65  66
67 68 69 70 71 72 73 74  75  76  77  78
79 80 81 82 83 84 85 86  87  88  89  90  91
92 93 94 95 96 97 98 99 100 101 102 103 104 105

PL/I

<lang pli>(fofl, size): floyd: procedure options (main); /* Floyd's Triangle. Wiki 12 July 2012 */

  declare (i, m, n) fixed (10), (j, k, w, nr) fixed binary;
  put list ('How many rows do you want?');
  get list (nr);   /* the number of rows   */
  n = nr*(nr+1)/2; /* the total number of values */
  j,k = 1; m = n - nr + 1;
  do i = 1 to n;
     put edit (i) ( x(1), f(length(trim(m))) );
     if k > 1 then do; k = k - 1; m = m + 1; end;
     else do; k,j = j + 1; m = n - nr + 1; put skip; end;
  end;

end floyd;</lang>

Output:
How many rows do you want?
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15

How many rows do you want? 
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
 16 17 18 19 20 21
 22 23 24 25 26 27 28
 29 30 31 32 33 34 35 36
 37 38 39 40 41 42 43 44  45
 46 47 48 49 50 51 52 53  54  55
 56 57 58 59 60 61 62 63  64  65  66
 67 68 69 70 71 72 73 74  75  76  77  78
 79 80 81 82 83 84 85 86  87  88  89  90  91
 92 93 94 95 96 97 98 99 100 101 102 103 104 105

Final row for n=45:
 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035

Prolog

Works with SWI-Prolog version 6.5.3 <lang Prolog>floyd(N) :- forall(between(1, N, I), ( forall(between(1,I, J), ( Last is N * (N-1)/2+J, V is I * (I-1) /2 + J, get_column(Last, C), sformat(AR, '~~t~~w~~~w| ', [C]), sformat(AF, AR, [V]), writef(AF))), nl)).

get_column(Last, C) :- name(Last, N1), length(N1,C). </lang> Output :

 ?- floyd(5).
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 
true.

 ?- floyd(14).
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 
16 17 18 19 20 21 
22 23 24 25 26 27 28 
29 30 31 32 33 34 35 36 
37 38 39 40 41 42 43 44  45 
46 47 48 49 50 51 52 53  54  55 
56 57 58 59 60 61 62 63  64  65  66 
67 68 69 70 71 72 73 74  75  76  77  78 
79 80 81 82 83 84 85 86  87  88  89  90  91 
92 93 94 95 96 97 98 99 100 101 102 103 104 105 
true.

PureBasic

<lang PureBasic>Procedure.i sumTo(n)

 Protected r,i
 For i=1 To n 
   r+i
 Next 
 ProcedureReturn r.i

EndProcedure

[1]
array rsA(n)... string-lengths of the numbers
in the bottom row
[2]
sumTo(i-1)+1 to sumTo(i)
          ; 11 12 13 14 15
 ; here k is the column-index for array rsA(k)

Procedure.s FloydsTriangle(n)

 Protected r.s,s.s,t.s,i,j,k
 ; [1]
 Dim rsA(n)
 i=0
 For j=sumTo(n-1)+1 To sumTo(n)
   i+1
   rsA(i)=Len(Str(j))
 Next
 ; [2]
 For i=1 To n 
   t.s="":k=0
   For j=sumTo(i-1)+1 To sumTo(i)
     k+1:t.s+RSet(Str(j),rsA(k)," ")+" "
   Next 
   r.s+RTrim(t.s)+Chr(13)+Chr(10)
 Next 
 r.s=Left(r.s,Len(r.s)-2)
 ProcedureReturn r.s

EndProcedure

If OpenConsole()

 n=5
 r.s=FloydsTriangle(n)
 PrintN(r.s)
 
 n=14
 r.s=FloydsTriangle(n)
 PrintN(r.s)
 
 Print(#crlf$ + #crlf$ + "Press ENTER to exit"): Input()
 CloseConsole()

EndIf</lang>

Sample Output

 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35 36
37 38 39 40 41 42 43 44  45
46 47 48 49 50 51 52 53  54  55
56 57 58 59 60 61 62 63  64  65  66
67 68 69 70 71 72 73 74  75  76  77  78
79 80 81 82 83 84 85 86  87  88  89  90  91
92 93 94 95 96 97 98 99 100 101 102 103 104 105

Python

<lang python>>>> def floyd(rowcount=5): rows = 1 while len(rows) < rowcount: n = rows[-1][-1] + 1 rows.append(list(range(n, n + len(rows[-1]) + 1))) return rows

>>> floyd() [[1], [2, 3], [4, 5, 6], [7, 8, 9, 10], [11, 12, 13, 14, 15]] >>> def pfloyd(rows=[[1], [2, 3], [4, 5, 6], [7, 8, 9, 10]]): colspace = [len(str(n)) for n in rows[-1]] for row in rows: print( ' '.join('%*i' % space_n for space_n in zip(colspace, row)))


>>> pfloyd() 1 2 3 4 5 6 7 8 9 10 >>> pfloyd(floyd(5))

1
2  3
4  5  6
7  8  9 10

11 12 13 14 15 >>> pfloyd(floyd(14))

1
2  3
4  5  6
7  8  9 10

11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 >>> </lang>

Alternately (using the mathematical formula for each row directly): <lang python>def floyd(rowcount=5):

   return [list(range(i*(i-1)//2+1, i*(i+1)//2+1))
           for i in range(1, rowcount+1)]</lang>

Racket

<lang racket>

  1. lang racket

(require math)

(define (tri n)

 (if (zero? n) 0 (triangle-number n)))

(define (floyd n)

 (define (width x) (string-length (~a x)))
 (define (~n x c) (~a x 
                      #:width (width (+ (tri (- n 1)) 1 c))
                      #:align 'right #:left-pad-string " "))
 (for ([r n])
   (for ([c (+ r 1)]) 
     (display (~a (~n (+ (tri r) 1 c) c) " ")))
   (newline)))

(floyd 5) (floyd 14) </lang> Output:

 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 
16 17 18 19 20 21 
22 23 24 25 26 27 28 
29 30 31 32 33 34 35 36 
37 38 39 40 41 42 43 44  45 
46 47 48 49 50 51 52 53  54  55 
56 57 58 59 60 61 62 63  64  65  66 
67 68 69 70 71 72 73 74  75  76  77  78 
79 80 81 82 83 84 85 86  87  88  89  90  91 
92 93 94 95 96 97 98 99 100 101 102 103 104 105 

REXX

version 1

<lang rexx> /* REXX ***************************************************************

  • Parse Arg rowcount
  • 12.07.2012 Walter Pachl - translated from Python
                                                                                                                                            • /

Parse Arg rowcount col=0 ll= /* last line of triangle */ Do j=rowcount*(rowcount-1)/2+1 to rowcount*(rowcount+1)/2

 col=col+1                         /* column number                 */ 
 ll=ll j                           /* build last line               */ 
 len.col=length(j)                 /* remember length of column     */ 
 End                                                                   

Do i=1 To rowcount-1 /* now do and output the rest */

 ol=                                                                 
 col=0                                                                 
 Do j=i*(i-1)/2+1 to i*(i+1)/2     /* elements of line i            */ 
   col=col+1                                                           
   ol=ol right(j,len.col)          /* element in proper length      */ 
   end                                                                 
 Say ol                            /* output ith line               */ 
 end                                                                   

Say ll /* output last line */ </lang> Output:

n=5
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15 

n=14  
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
 16 17 18 19 20 21
 22 23 24 25 26 27 28
 29 30 31 32 33 34 35 36
 37 38 39 40 41 42 43 44  45
 46 47 48 49 50 51 52 53  54  55
 56 57 58 59 60 61 62 63  64  65  66
 67 68 69 70 71 72 73 74  75  76  77  78
 79 80 81 82 83 84 85 86  87  88  89  90  91
 92 93 94 95 96 97 98 99 100 101 102 103 104 105 

version 2

This REXX version uses a simple formula to calculate the maximum value (triangle element) displayed. <lang rexx>/*REXX program constructs & displays Floyd's triangle for any number of specified rows.*/ parse arg rows .; if rows== then rows=5 /*Not specified? Then use the default.*/ mx=rows * (rows+1) % 2 /*calculate maximum value of any value.*/ say 'displaying a ' rows " row Floyd's triangle:" /*show header for the triangle.*/ say

  1. =1; do r=1 for rows; i=0; _= /*construct Floyd's triangle row by row*/
           do #=#  for r;      i=i+1            /*start to construct a row of triangle.*/
           _=_ right(#, length(mx-rows+i))      /*build a row of the Floyd's triangle. */
           end   /*#*/
       say substr(_,2)                          /*remove 1st leading blank in the line,*/
       end       /*r*/                          /* [↑]   introduced by first abutment. */
                                                /*stick a fork in it,  we're all done. */</lang>

output   when using the default input:

displaying a  5  row Floyd's triangle:

 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15

output   when using the input of:   14

displaying a  14  row Floyd's triangle:

 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35 36
37 38 39 40 41 42 43 44  45
46 47 48 49 50 51 52 53  54  55
56 57 58 59 60 61 62 63  64  65  66
67 68 69 70 71 72 73 74  75  76  77  78
79 80 81 82 83 84 85 86  87  88  89  90  91
92 93 94 95 96 97 98 99 100 101 102 103 104 105

output (only showing the last row) when using the input of:   45

  ··· 44 rows not shown ··· 
991  992  993  994  995  996  997  998  999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035

version 3, hexadecimal

<lang rexx>/*REXX program constructs & displays Floyd's triangle for any number of rows in base 16.*/ parse arg rows .; if rows== then rows=6 /*Not specified? Then use the default.*/ mx=rows * (rows+1) % 2 /*calculate maximum value of any value.*/ say 'displaying a ' rows " row Floyd's triangle in base 16:"; say /*show triangle hdr*/

  1. =1
   do     r=1  for rows;   i=0;         _=      /*construct Floyd's triangle row by row*/
       do #=#  for r;      i=i+1                /*start to construct a row of triangle.*/
       _=_ right(d2x(#),length(d2x(mx-rows+i))) /*build a row of the Floyd's triangle. */
       end   /*#*/
   say substr(_,2)                              /*remove 1st leading blank in the line,*/
   end       /*r*/                              /* [↑]   introduced by first abutment. */
                                                /*stick a fork in it,  we're all done. */</lang>

output   when using the default input:

displaying a  6  row Floyd's triangle in base 16:

 1
 2  3
 4  5  6
 7  8  9  A
 B  C  D  E  F
10 11 12 13 14 15

output   when using the input of:   23

displaying a  23  row Floyd's triangle in base 16:

 1
 2  3
 4  5   6
 7  8   9   A
 B  C   D   E   F
10 11  12  13  14  15
16 17  18  19  1A  1B  1C
1D 1E  1F  20  21  22  23  24
25 26  27  28  29  2A  2B  2C  2D
2E 2F  30  31  32  33  34  35  36  37
38 39  3A  3B  3C  3D  3E  3F  40  41  42
43 44  45  46  47  48  49  4A  4B  4C  4D  4E
4F 50  51  52  53  54  55  56  57  58  59  5A  5B
5C 5D  5E  5F  60  61  62  63  64  65  66  67  68  69
6A 6B  6C  6D  6E  6F  70  71  72  73  74  75  76  77  78
79 7A  7B  7C  7D  7E  7F  80  81  82  83  84  85  86  87  88
89 8A  8B  8C  8D  8E  8F  90  91  92  93  94  95  96  97  98  99
9A 9B  9C  9D  9E  9F  A0  A1  A2  A3  A4  A5  A6  A7  A8  A9  AA  AB
AC AD  AE  AF  B0  B1  B2  B3  B4  B5  B6  B7  B8  B9  BA  BB  BC  BD  BE
BF C0  C1  C2  C3  C4  C5  C6  C7  C8  C9  CA  CB  CC  CD  CE  CF  D0  D1  D2
D3 D4  D5  D6  D7  D8  D9  DA  DB  DC  DD  DE  DF  E0  E1  E2  E3  E4  E5  E6  E7
E8 E9  EA  EB  EC  ED  EE  EF  F0  F1  F2  F3  F4  F5  F6  F7  F8  F9  FA  FB  FC  FD
FE FF 100 101 102 103 104 105 106 107 108 109 10A 10B 10C 10D 10E 10F 110 111 112 113 114

version 4, up to base 90

This REXX version could be extended to even higher bases, all that is needed is to append more viewable characters to express "higher" numerals   ("digits" in base X). <lang rexx>/*REXX program constructs/shows Floyd's triangle for any number of rows in any base ≤90.*/ parse arg rows radx . /*obtain optional arguments from the CL*/ if rows== | rows=="," then rows= 5 /*Not specified? Then use the default.*/ if radx== | radx=="," then radx=10 /* " " " " " " */ mx=rows * (rows+1) % 2 /*calculate maximum value of any value.*/ say 'displaying a ' rows " row Floyd's triangle in base" radx':'; say /*display hdr*/

  1. =1
    do     r=1  for rows;   i=0;         _=     /*construct Floyd's triangle row by row*/
        do #=#  for r;      i=i+1               /*start to construct a row of triangle.*/
        _=_ right(base(#, radx),  length(base(mx-rows+i, radx)))   /*build triangle row*/
        end   /*#*/
    say substr(_,2)                             /*remove 1st leading blank in the line,*/
    end       /*r*/                             /* [↑]   introduced by first abutment. */

exit /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ base: procedure; parse arg x 1 ox,toB,inB /*obtain number, toBase, inBase. */

     @abc='abcdefghijklmnopqrstuvwxyz'                /*lowercase Latin alphabet.      */
     @abcU=@abc;       upper @abcU                    /*go whole hog and extend 'em.   */
     @@@='0123456789'@abc || @abcU                    /*prefix 'em with numeric digits.*/
     @@@=@@@'<>[]{}()?~!@#$%^&*_=|\/;:¢¬≈'            /*add some special chars as well.*/
                                  /*handles up to base 90,  all chars must be viewable.*/
     numeric digits 1000                              /*what the hey, support gihugeics*/
     mxB=length(@@@)                                  /*max base (radix) supported here*/
     if toB== | toB=="," then toB=10                /*if skipped, assume default (10)*/
     if inB== | inB=="," then inB=10                /* "    "        "      "      " */
     if inB<2   | inb>mxB  then call erb 'inBase',inB /*invalid/illegal arg:   inBase. */
     if toB<2   | tob>mxB  then call erb 'toBase',toB /*    "      "     "     toBase. */
     if x==              then call erm              /*    "      "     "     number. */
                                 sigX=left(x,1)
     if pos(sigX,'-+')\==0  then x=substr(x,2)        /*X  number has a leading sign?  */
                            else sigX=                /*           ··· no leading sign.*/
     #=0;  do j=1  for length(x)                      /*convert X, base inB ──► base 10*/
           _=substr(x, j, 1)                          /*pick off a  numeral  from  X.  */
           v=pos(_, @@@)                              /*get the value of this "digit". */
           if v==0 | v>inB  then call erd x,j,inB     /*is this an illegal "numeral" ? */
           #=#*inB+v-1                                /*construct new num, dig by dig. */
           end   /*j*/
     y=
           do  while  # >= toB                        /*convert #, base 10 ──► base toB*/
           y=substr(@@@, (#//toB)+1, 1)y              /*construct the number for output*/
           #=#%toB                                    /* ··· and whittle  #  down also.*/
           end   /*while*/
     y=sigX || substr(@@@, #+1, 1)y                   /*prepend the sign if it existed.*/
     return y                                         /*return the number in base  toB.*/

/*───────────────────────────────────────────────────────────────────────────────────────*/ erb: call ser 'illegal' arg(2) "base:" arg(1) "must be in range: 2──►" mxB erd: call ser 'illegal "digit" in' x":" _ erm: call ser 'no argument specified.' ser: say; say '*** error! ***'; say arg(1); say; exit 13</lang> output   when using the input of:   6   2

displaying a  6  row Floyd's triangle in base 2:
 
    1
   10    11
  100   101   110
  111  1000  1001  1010
 1011  1100  1101  1110  1111
10000 10001 10010 10011 10100 10101

output   when using the input of:   23   2

displaying a  12  row Floyd's triangle in base 2:

      1
     10      11
    100     101     110
    111    1000    1001    1010
   1011    1100    1101    1110    1111
  10000   10001   10010   10011   10100   10101
  10110   10111   11000   11001   11010   11011   11100
  11101   11110   11111  100000  100001  100010  100011  100100
 100101  100110  100111  101000  101001  101010  101011  101100  101101
 101110  101111  110000  110001  110010  110011  110100  110101  110110  110111
 111000  111001  111010  111011  111100  111101  111110  111111 1000000 1000001 1000010
1000011 1000100 1000101 1000110 1000111 1001000 1001001 1001010 1001011 1001100 1001101 1001110

output   when using the input of:   40   81

displaying a  40  row Floyd's triangle in base 81:

 1
 2  3
 4  5  6
 7  8  9  a
 b  c  d  e  f
 g  h  i  j  k  l
 m  n  o  p  q  r  s
 t  u  v  w  x  y  z  A
 B  C  D  E  F  G  H  I  J
 K  L  M  N  O  P  Q  R  S  T
 U  V  W  X  Y  Z  <  >  [  ]  {
 }  (  )  ?  ~  !  @  #  $  %  ^  &
 *  _ 10 11 12 13 14 15 16 17 18 19 1a
1b 1c 1d 1e 1f 1g 1h 1i 1j 1k 1l 1m 1n 1o
1p 1q 1r 1s 1t 1u 1v 1w 1x 1y 1z 1A 1B 1C 1D
1E 1F 1G 1H 1I 1J 1K 1L 1M 1N 1O 1P 1Q 1R 1S 1T
1U 1V 1W 1X 1Y 1Z 1< 1> 1[ 1] 1{ 1} 1( 1) 1? 1~ 1!
1@ 1# 1$ 1% 1^ 1& 1* 1_ 20 21 22 23 24 25 26 27 28 29
2a 2b 2c 2d 2e 2f 2g 2h 2i 2j 2k 2l 2m 2n 2o 2p 2q 2r 2s
2t 2u 2v 2w 2x 2y 2z 2A 2B 2C 2D 2E 2F 2G 2H 2I 2J 2K 2L 2M
2N 2O 2P 2Q 2R 2S 2T 2U 2V 2W 2X 2Y 2Z 2< 2> 2[ 2] 2{ 2} 2( 2)
2? 2~ 2! 2@ 2# 2$ 2% 2^ 2& 2* 2_ 30 31 32 33 34 35 36 37 38 39 3a
3b 3c 3d 3e 3f 3g 3h 3i 3j 3k 3l 3m 3n 3o 3p 3q 3r 3s 3t 3u 3v 3w 3x
3y 3z 3A 3B 3C 3D 3E 3F 3G 3H 3I 3J 3K 3L 3M 3N 3O 3P 3Q 3R 3S 3T 3U 3V
3W 3X 3Y 3Z 3< 3> 3[ 3] 3{ 3} 3( 3) 3? 3~ 3! 3@ 3# 3$ 3% 3^ 3& 3* 3_ 40 41
42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f 4g 4h 4i 4j 4k 4l 4m 4n 4o 4p 4q 4r
4s 4t 4u 4v 4w 4x 4y 4z 4A 4B 4C 4D 4E 4F 4G 4H 4I 4J 4K 4L 4M 4N 4O 4P 4Q 4R 4S
4T 4U 4V 4W 4X 4Y 4Z 4< 4> 4[ 4] 4{ 4} 4( 4) 4? 4~ 4! 4@ 4# 4$ 4% 4^ 4& 4* 4_ 50 51
52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f 5g 5h 5i 5j 5k 5l 5m 5n 5o 5p 5q 5r 5s 5t 5u
5v 5w 5x 5y 5z 5A 5B 5C 5D 5E 5F 5G 5H 5I 5J 5K 5L 5M 5N 5O 5P 5Q 5R 5S 5T 5U 5V 5W 5X 5Y
5Z 5< 5> 5[ 5] 5{ 5} 5( 5) 5? 5~ 5! 5@ 5# 5$ 5% 5^ 5& 5* 5_ 60 61 62 63 64 65 66 67 68 69 6a
6b 6c 6d 6e 6f 6g 6h 6i 6j 6k 6l 6m 6n 6o 6p 6q 6r 6s 6t 6u 6v 6w 6x 6y 6z 6A 6B 6C 6D 6E 6F 6G
6H 6I 6J 6K 6L 6M 6N 6O 6P 6Q 6R 6S 6T 6U 6V 6W 6X 6Y 6Z 6< 6> 6[ 6] 6{ 6} 6( 6) 6? 6~ 6! 6@ 6# 6$
6% 6^ 6& 6* 6_ 70 71 72 73 74 75 76 77 78 79 7a 7b 7c 7d 7e 7f 7g 7h 7i 7j 7k 7l 7m 7n 7o 7p 7q 7r 7s
7t 7u 7v 7w 7x 7y 7z 7A 7B 7C 7D 7E 7F 7G 7H 7I 7J 7K 7L 7M 7N 7O 7P 7Q 7R 7S 7T 7U 7V 7W 7X 7Y 7Z 7< 7>
7[ 7] 7{ 7} 7( 7) 7? 7~ 7! 7@ 7# 7$ 7% 7^ 7& 7* 7_ 80 81 82 83 84 85 86 87 88 89 8a 8b 8c 8d 8e 8f 8g 8h 8i
8j 8k 8l 8m 8n 8o 8p 8q 8r 8s 8t 8u 8v 8w 8x 8y 8z 8A 8B 8C 8D 8E 8F 8G 8H 8I 8J 8K 8L 8M 8N 8O 8P 8Q 8R 8S 8T
8U 8V 8W 8X 8Y 8Z 8< 8> 8[ 8] 8{ 8} 8( 8) 8? 8~ 8! 8@ 8# 8$ 8% 8^ 8& 8* 8_ 90 91 92 93 94 95 96 97 98 99 9a 9b 9c
9d 9e 9f 9g 9h 9i 9j 9k 9l 9m 9n 9o 9p 9q 9r 9s 9t 9u 9v 9w 9x 9y 9z 9A 9B 9C 9D 9E 9F 9G 9H 9I 9J 9K 9L 9M 9N 9O 9P
9Q 9R 9S 9T 9U 9V 9W 9X 9Y 9Z 9< 9> 9[ 9] 9{ 9} 9( 9) 9? 9~ 9! 9@ 9# 9$ 9% 9^ 9& 9* 9_ a0 a1 a2 a3 a4 a5 a6 a7 a8 a9 aa

Ring

<lang ring> rows = 10 n = 0 for r = 1 to rows

   for c = 1 to r  
       n = n + 1
       see string(n) + " " 
   next 
   see nl

next </lang>

Ruby

<lang ruby>def floyd(rows)

 max = (rows * (rows + 1)) / 2
 widths = ((max - rows + 1)..max).map {|n| n.to_s.length + 1}
 n = 0
 rows.times do |r|
   puts (0..r).map {|i| n += 1; "%#{widths[i]}d" % n}.join
 end

end

floyd(5) floyd(14)</lang>

Output:
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
 16 17 18 19 20 21
 22 23 24 25 26 27 28
 29 30 31 32 33 34 35 36
 37 38 39 40 41 42 43 44  45
 46 47 48 49 50 51 52 53  54  55
 56 57 58 59 60 61 62 63  64  65  66
 67 68 69 70 71 72 73 74  75  76  77  78
 79 80 81 82 83 84 85 86  87  88  89  90  91
 92 93 94 95 96 97 98 99 100 101 102 103 104 105

Run BASIC

<lang runbasic>input "Number of rows: "; rows dim colSize(rows) for col=1 to rows

   colSize(col) = len(str$(col + rows * (rows-1)/2))

next

thisNum = 1 for r = 1 to rows

   for col = 1 to r
       print right$( "  "+str$(thisNum), colSize(col)); " ";
       thisNum = thisNum + 1
   next
   print

next</lang>

Number of rows: ?14
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 
16 17 18 19 20 21 
22 23 24 25 26 27 28 
29 30 31 32 33 34 35 36 
37 38 39 40 41 42 43 44  45 
46 47 48 49 50 51 52 53  54  55 
56 57 58 59 60 61 62 63  64  65  66 
67 68 69 70 71 72 73 74  75  76  77  78 
79 80 81 82 83 84 85 86  87  88  89  90  91 
92 93 94 95 96 97 98 99 100 101 102 103 104 105 

Scala

<lang scala>def floydstriangle( n:Int ) {

 val s = (1 to n)
 val t = s map {i => (s take(i-1) sum) + 1}
 
 (s zip t) foreach { n => 
   var m = n._2; 
   for( i <- 0 until n._1 ) {
     val w = (t.last + i).toString.length + 1  // Column width from last row
     print("           " + m takeRight w )
     m+=1
   }
   print("\n")
 }

}

// Test floydstriangle(5) floydstriangle(14)</lang>

Output:
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15

  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
 16 17 18 19 20 21
 22 23 24 25 26 27 28
 29 30 31 32 33 34 35 36
 37 38 39 40 41 42 43 44  45
 46 47 48 49 50 51 52 53  54  55
 56 57 58 59 60 61 62 63  64  65  66
 67 68 69 70 71 72 73 74  75  76  77  78
 79 80 81 82 83 84 85 86  87  88  89  90  91
 92 93 94 95 96 97 98 99 100 101 102 103 104 105

Seed7

<lang seed7>$ include "seed7_05.s7i";

const proc: writeFloyd (in integer: rows) is func

 local
   var integer: number is 1;
   var integer: numBeforeLastLine is 0;
   var integer: line is 0;
   var integer: column is 0;
 begin
   numBeforeLastLine := rows * pred(rows) div 2;
   for line range 1 to rows do
     for column range 1 to line do
       if column <> 1 then
         write(" ");
       end if;
       write(number lpad length(str(numBeforeLastLine + column)));
       incr(number);
     end for;
     writeln;
   end for;
 end func;

const proc: main is func

 begin
   writeFloyd(5);
   writeFloyd(14);
 end func;</lang>

Output:

 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35 36
37 38 39 40 41 42 43 44  45
46 47 48 49 50 51 52 53  54  55
56 57 58 59 60 61 62 63  64  65  66
67 68 69 70 71 72 73 74  75  76  77  78
79 80 81 82 83 84 85 86  87  88  89  90  91
92 93 94 95 96 97 98 99 100 101 102 103 104 105

Sidef

<lang ruby>func floyd(rows, n=1) {

   var max = Math.range_sum(1, rows);
   var widths = (max-rows .. max-1 -> map{(.+n).to_s.len});
   { |r|
       say %'#{1..r -> map{|i| "%#{widths[i-1]}d" % n++}.join(" ")}';
   } * rows;

}

floyd(5); # or: floyd(5, 88); floyd(14); # or: floyd(14, 900);</lang>

Output:
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
 1
 2  3
 4  5  6
 7  8  9 10
11 12 13 14 15
16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31 32 33 34 35 36
37 38 39 40 41 42 43 44  45
46 47 48 49 50 51 52 53  54  55
56 57 58 59 60 61 62 63  64  65  66
67 68 69 70 71 72 73 74  75  76  77  78
79 80 81 82 83 84 85 86  87  88  89  90  91
92 93 94 95 96 97 98 99 100 101 102 103 104 105

Tcl

<lang tcl>proc floydTriangle n {

   # Compute the column widths
   for {set i [expr {$n*($n-1)/2+1}]} {$i <= $n*($n+1)/2} {incr i} {

lappend w [string length $i]

   }
   # Print the triangle
   for {set i 0; set j 1} {$j <= $n} {incr j} {

for {set p -1; set k 0} {$k < $j} {incr k} { puts -nonewline [format "%*d " [lindex $w [incr p]] [incr i]] } puts ""

   }

}

  1. Demonstration

puts "Floyd 5:" floydTriangle 5 puts "Floyd 14:" floydTriangle 14</lang>

Output:
Floyd 5:
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 
Floyd 14:
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 
16 17 18 19 20 21 
22 23 24 25 26 27 28 
29 30 31 32 33 34 35 36 
37 38 39 40 41 42 43 44  45 
46 47 48 49 50 51 52 53  54  55 
56 57 58 59 60 61 62 63  64  65  66 
67 68 69 70 71 72 73 74  75  76  77  78 
79 80 81 82 83 84 85 86  87  88  89  90  91 
92 93 94 95 96 97 98 99 100 101 102 103 104 105 

TXR

<lang txrlisp>(defun flotri (n)

 (let* ((last (trunc (* n (+ n 1)) 2))
        (colw (mapcar [chain tostring length]
                      (range (- last n -1) last)))
        (x 0))
   (each ((r (range* 0 n)))
     (each ((c (range 0 r)))
       (format t " ~*a" [colw c] (inc x)))
     (put-line))))

(defun usage (msg)

 (put-line `error: @msg`)
 (put-line `usage:\n@(ldiff *full-args* *args*) <smallish-positive-integer>`)
 (exit 1))

(tree-case *args*

 ((num blah . etc) (usage "too many arguments"))
 ((num) (flotri (int-str num)))
 (() (usage "need an argument")))</lang>
Output:
$ txr floyds-triangle.tl
error: need an argument
usage:
txr floyds-triangle.tl <smallish-positive-integer>
$ txr floyds-triangle.txr 1 2
error: too many arguments
usage:
txr floyds-triangle.tl <smallish-positive-integer>
$ txr floyds-triangle.tl 5
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
$ txr floyds-triangle.tl 14
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
 16 17 18 19 20 21
 22 23 24 25 26 27 28
 29 30 31 32 33 34 35 36
 37 38 39 40 41 42 43 44  45
 46 47 48 49 50 51 52 53  54  55
 56 57 58 59 60 61 62 63  64  65  66
 67 68 69 70 71 72 73 74  75  76  77  78
 79 80 81 82 83 84 85 86  87  88  89  90  91
 92 93 94 95 96 97 98 99 100 101 102 103 104 105

VBScript

Works with: Windows Script Host version *

<lang VBScript> ' Read the number of rows to use.. intRows = WScript.StdIn.ReadLine

' Get the first number of the final row so we can calculate widths... intLastRowStart = (intRows ^ 2 - intRows) \ 2 + 1

For i = 1 To intRows intLastRow = intLastRowStart For j = 1 To i k = k + 1 WScript.StdOut.Write Space(Len(intLastRow) - Len(k)) & k & " " intLastRow = intLastRow + 1 Next WScript.StdOut.WriteLine "" Next </lang>

XPL0

<lang XPL0>include c:\cxpl\codes; \include 'code' declarations

func IntLen(N); \Return number of digits in a positive integer int N; int I; for I:= 1 to 20 do

   [N:= N/10;  if N=0 then return I];

proc Floyd(N); \Display Floyd's triangle int N; int M, Row, Col; real F; [M:= (N-1+1)*(N-1)/2; \last Floyd number on second to last row F:= 1.0; \Floyd number counter for Row:= 1 to N do

   [for Col:= 1 to Row do
       [Format(IntLen(M+Col)+1, 0);  RlOut(0, F);  F:= F+1.0];
   CrLf(0);
   ];

]; \Floyd

[Floyd(5); Floyd(14); ]</lang>

Output:

  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
  1
  2  3
  4  5  6
  7  8  9 10
 11 12 13 14 15
 16 17 18 19 20 21
 22 23 24 25 26 27 28
 29 30 31 32 33 34 35 36
 37 38 39 40 41 42 43 44  45
 46 47 48 49 50 51 52 53  54  55
 56 57 58 59 60 61 62 63  64  65  66
 67 68 69 70 71 72 73 74  75  76  77  78
 79 80 81 82 83 84 85 86  87  88  89  90  91
 92 93 94 95 96 97 98 99 100 101 102 103 104 105

zkl

Format last line and then fit each line to that format (which is wider than terminal width before formating breaks down (at 10 digit numbers)): <lang zkl>fcn lcNum(row){(row*(row+1)/2+1)} // lazy caterer's sequence fcn floydsTriangle(rows){

  fmt:=[lcNum(rows-1)..lcNum(rows)-1].pump(String,fcn(n){
     String("%",n.toString().len(),"d ")}); // eg "%2d %2d %3d %3d"
  foreach row in (rows){
    ns:=[lcNum(row)..lcNum(row+1)-1].walk(); // eg L(4.5,6)
    fmt[0,ns.len()*4].fmt(ns.xplode()).println(); // eg "%2d %2d %2d ".fmt(4,5,6)
  }

} floydsTriangle(5); println(); floydsTriangle(14);</lang>

Output:
 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 

 1 
 2  3 
 4  5  6 
 7  8  9 10 
11 12 13 14 15 
16 17 18 19 20 21 
22 23 24 25 26 27 28 
29 30 31 32 33 34 35 36 
37 38 39 40 41 42 43 44  45 
46 47 48 49 50 51 52 53  54  55 
56 57 58 59 60 61 62 63  64  65  66 
67 68 69 70 71 72 73 74  75  76  77  78 
79 80 81 82 83 84 85 86  87  88  89  90  91 
92 93 94 95 96 97 98 99 100 101 102 103 104 105 

ZX Spectrum Basic

<lang zxbasic>10 LET n=10: LET j=1: LET col=1 20 FOR r=1 TO n 30 FOR j=j TO j+r-1 40 PRINT TAB (col);j; 50 LET col=col+3 60 NEXT j 70 PRINT 80 LET col=1 90 NEXT r</lang>