Loops/Nested
You are encouraged to solve this task according to the task description, using any language you may know.
Show a nested loop which searches two-dimensional array filled with random number uniformly distributed on [1..20]. The loops iterate rows and columns of the array printing the iterated elements of, until the value 20 is met.
Ada
<lang ada> with Ada.Text_IO; use Ada.Text_IO; with Ada.Numerics.Discrete_Random;
procedure Test_Loop_Nested is
type Value_Type is range 1..20;
package Random_Values is new Ada.Numerics.Discrete_Random (Value_Type);
use Random_Values;
Dice : Generator;
A : array (1..10, 1..10) of Value_Type :=
(others => (others => Random (Dice)));
begin
Outer :
for I in A'Range (1) loop
for J in A'Range (2) loop
Put (Value_Type'Image (A (I, J)));
exit Outer when A (I, J) = 20;
end loop;
New_Line;
end loop Outer;
end Test_Loop_Nested; </lang> Sample output:
16 3 1 17 13 5 4 2 19 1 5 5 17 15 17 2 5 5 17 13 16 10 10 20
AutoHotkey
<lang AutoHotkey>loop, 10 {
i := A_Index
loop, 10
{
j := A_Index Random, a%i%%j%, 1, 20 } }
loop, 10 {
i := A_Index
loop, 10
{
j := A_Index if (a%i%%j% == 20) goto finish
}
}
finish: msgbox % "a[" . i . "][" . j . "]" is 20 return</lang>
C
Using goto (note: gotos are considered harmful): <lang c>#include <stdlib.h>
- include <time.h>
- include <stdio.h>
int main() {
int a[10][10], i, j;
srand(time(NULL));
for (i = 0; i < 10; i++)
for (j = 0; j < 10; j++)
a[i][j] = rand() % 20 + 1;
for (i = 0; i < 10; i++) {
for (j = 0; j < 10; j++) {
printf(" %d", a[i][j]);
if (a[i][j] == 20)
goto Done;
}
printf("\n");
}
Done:
printf("\n");
return 0;
}</lang>
Common Lisp
<lang lisp>(let ((a (make-array '(10 10))))
(dotimes (i 10)
(dotimes (j 10)
(setf (aref a i j) (1+ (random 20)))))
(block outer
(dotimes (i 10)
(dotimes (j 10)
(princ " ")
(princ (aref a i j))
(if (= 20 (aref a i j))
(return-from outer)))
(terpri))
(terpri)))</lang>
Forth
<lang forth> include random.fs
10 constant X 10 constant Y
- ,randoms ( range n -- ) 0 do dup random 1+ , loop drop ;
create 2darray 20 X Y * ,randoms
- main
Y 0 do
cr
X 0 do
j X * i + cells 2darray + @
dup .
20 = if unloop unloop exit then
loop
loop ;
</lang>
Fortran
<lang fortran> program Example
implicit none
real :: ra(5,10) integer :: ia(5,10) integer :: i, j
call random_number(ra) ia = int(ra * 20.0) + 1
outer: do i = 1, size(ia, 1)
do j = 1, size(ia, 2)
write(*, "(i3)", advance="no") ia(i,j)
if (ia(i,j) == 20) exit outer
end do
write(*,*)
end do outer
end program Example </lang> Sample output:
14 2 1 11 8 1 14 11 3 15 7 15 16 6 7 17 3 20
Java
<lang java>import java.util.Random;
public class NestedLoopTest {
public static final Random gen = new Random();
public static void main(String[] args) {
int[][] a = new int[10][10];
for (int i = 0; i < a.length; i++)
for (int j = 0; j < a[i].length; j++)
a[i][j] = gen.nextInt(20) + 1;
Outer:
for (int i = 0; i < a.length; i++) {
for (int j = 0; j < a[i].length; j++) {
System.out.print(" " + a[i][j]);
if (a[i][j] == 20)
break Outer;
}
System.out.println();
}
System.out.println();
}
}</lang>
Perl
<lang perl>my $a = [ map [ map { int(rand(20)) + 1 } 1 .. 10 ], 1 .. 10];
Outer: foreach (@$a) {
foreach (@$_) {
print " $_";
if ($_ == 20) {
last Outer;
}
}
print "\n";
} print "\n";</lang>
PHP
<lang php><?php for ($i = 0; $i < 10; $i++)
for ($j = 0; $j < 10; $j++)
$a[$i][$j] = rand(1, 20);
foreach ($a as $row) {
foreach ($row as $element) {
echo " $element";
if ($element == 20)
break 2; // 2 is the number of loops we want to break out of
}
echo "\n";
} echo "\n"; ?></lang>
Ruby
As the break command only jumps out of the innermost loop, this task requires Ruby's catch/throw functionality.
<lang ruby>srand
ary = (1..20).to_a.shuffle.each_slice(4).to_a
p ary
catch :found_it do
for row in ary
for element in row
print "%2d " % element
throw :found_it if element == 20
end
puts ","
end
end
puts "done"</lang>
[[2, 12, 10, 4], [18, 11, 9, 3], [14, 15, 7, 17], [6, 19, 8, 13], [1, 20, 16, 5]] 2 12 10 4 , 18 11 9 3 , 14 15 7 17 , 6 19 8 13 , 1 20 done
Tcl
Tcl only supports single-level breaks; exiting more deeply nested looping requires the use of exceptions, which are considerably more verbose before Tcl 8.6.
<lang tcl>set ary [subst [lrepeat 10 [lrepeat 5 {[expr int(rand()*20+1)]}]]]
try {
foreach row $ary {
foreach col $row {
puts -nonewline [format %3s $col]
if {$col == 20} {
throw MULTIBREAK "we're done"
}
}
puts ,
}
} trap MULTIBREAK {} {} puts " done"</lang> Sample output:
12 13 14 13 15, 1 14 7 16 3, 12 11 5 1 9, 12 5 1 4 2, 6 11 11 4 11, 7 14 20 done