# Four sides of square

Four sides of square is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Fill with 1's the four sides of square. The rest of the square should be filled with 0's.
If you can please use GUI
Four sides of square - image

## 11l

Translation of: Python
```V size = 9
L(row) 0 .< size
L(col) 0 .< size
I row == 0 | row == size - 1 | col == 0 | col == size - 1
print(‘1’, end' ‘ ’)
E
print(‘0’, end' ‘ ’)
print()```
Output:
```1 1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 1 1 1 1 1 1 1 1
```

## Action!

```;;; draw a matrix with 1s on the edges and 0s elsewhere

;;; draws a matrix with height and width = n with 1s on the edges
PROC drawSquare( INT n )
CARD i, j
FOR i = 1 TO n DO
FOR j = 1 TO n DO
Put(' )
IF i = 1 OR i = n OR j = 1 OR j = n THEN Put('1) ELSE Put('0) FI
OD
PutE()
OD
RETURN

PROC Main()
drawSquare( 6 )
PutE()
drawSquare( 7 )
RETURN```
Output:
``` 1 1 1 1 1 1
1 0 0 0 0 1
1 0 0 0 0 1
1 0 0 0 0 1
1 0 0 0 0 1
1 1 1 1 1 1

1 1 1 1 1 1 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 1 1 1 1 1 1
```

```with Ada.Text_Io;

procedure Four_Sides is

type Matrix_Type is array (Natural range <>, Natural range <>) of Character;

function Hollow (Length : Natural) return Matrix_Type is
begin
return M : Matrix_Type (1 .. Length, 1 .. Length) do
for Row in M'Range(1) loop
for Col in M'Range (2) loop
M (Row, Col) := (if Row in M'First (1) | M'Last (1) or
Col in M'First (2) | M'Last (2)
then '1' else '0');
end loop;
end loop;
end return;
end Hollow;

procedure Put (M : Matrix_Type) is
begin
for Row in M'Range (1) loop
for Col in M'Range (2) loop
end loop;
end loop;
end Put;

begin
Put (Hollow (Length => Natural'Value (Ada.Command_Line.Argument (1))));
exception
when others =>
end Four_Sides;
```
Output:
```\$ ./four_sides 4
1 1 1 1
1 0 0 1
1 0 0 1
1 1 1 1
\$ ./four_sides 1
1
\$ ./four_sides 0
\$ ./four_sides 2
1 1
1 1
\$ ./four_sides -1
Usage: ./four_sides <length>
```

## ALGOL 68

```BEGIN # draw a matrix with 1s on the edges and 0s elsewhere             #
# draws a matrix with height and width = n with 1s on the edges     #
PROC draw square = ( INT n )VOID:
FOR i TO n DO
FOR j TO n DO
print( ( " ", whole( ABS ( i = 1 OR i = n OR j = 1 OR j = n ), 0 ) ) )
OD;
print( ( newline ) )
OD # draw square # ;
# test the draw square procedure #
draw square( 6 );
print( ( newline ) );
draw square( 7 )
END```
Output:
``` 1 1 1 1 1 1
1 0 0 0 0 1
1 0 0 0 0 1
1 0 0 0 0 1
1 0 0 0 0 1
1 1 1 1 1 1

1 1 1 1 1 1 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 1 1 1 1 1 1
```

## ALGOL W

```begin % draw a matrix with 1s on the edges and 0s elsewhere             %
% draws a matrix with height and width = n with 1s on the edges     %
procedure drawSquare ( integer value n ) ;
for i := 1 until n do begin
for j := 1 until n do begin
writeon( s_w := 0, if i = 1 or i = n or j = 1 or j = n then " 1" else " 0" )
end for_j ;
write()
end drawSquare ;
% test the draw square procedure %
drawSquare( 6 );
write();
drawSquare( 7 )
end.```
Output:
``` 1 1 1 1 1 1
1 0 0 0 0 1
1 0 0 0 0 1
1 0 0 0 0 1
1 0 0 0 0 1
1 1 1 1 1 1

1 1 1 1 1 1 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 1 1 1 1 1 1
```

## AppleScript

Defined in terms of a generic matrix function:

```------------------- FOUR SIDES OF SQUARE -----------------

-- fourSides :: Int -> [[Int]]
on fourSides(n)
-- A matrix of dimension n in which edge values are 1,
-- and other values are zero.
script go
on |λ|(i, j)
if {1, n} contains i or {1, n} contains j then
1
else
0
end if
end |λ|
end script

matrix(n, n, go)
end fourSides

--------------------------- TEST -------------------------
on run
-- Matrices of dimension 1 .. 6

script test
on |λ|(n)
showMatrix(fourSides(n)) & linefeed & linefeed
end |λ|
end script

unlines(map(test, enumFromTo(1, 6)))
end run

------------------------- MATRICES -----------------------

-- matrix :: Int -> Int -> ((Int, Int) -> a) -> [[a]]
on matrix(nRows, nCols, f)
-- A matrix of a given number of columns and rows,
-- in which each value is a given function of its
-- (zero-based) column and row indices.
script go
property g : mReturn(f)'s |λ|

on |λ|(iRow)
set xs to {}
repeat with iCol from 1 to nCols
set end of xs to g(iRow, iCol)
end repeat
xs
end |λ|
end script

map(go, enumFromTo(1, nRows))
end matrix

-- showMatrix :: [[Maybe a]] -> String
on showMatrix(rows)
-- String representation of rows
-- as a matrix.

script showRow
on |λ|(a, row)
set {maxWidth, prevRows} to a
script showCell
on |λ|(acc, cell)
set {w, xs} to acc
if missing value is cell then
{w, xs & ""}
else
set s to cell as string
{max(w, length of s), xs & s}
end if
end |λ|
end script

set {rowMax, cells} to foldl(showCell, {0, {}}, row)
{max(maxWidth, rowMax), prevRows & {cells}}
end |λ|
end script

set {w, stringRows} to foldl(showRow, {0, {}}, rows)
script go
on |λ|(row)
unwords(map(justifyRight(w, space), row))
end |λ|
end script

unlines(map(go, stringRows))
end showMatrix

------------------------- GENERIC ------------------------

-- enumFromTo :: Int -> Int -> [Int]
on enumFromTo(m, n)
if m ≤ n then
set xs to {}
repeat with i from m to n
set end of xs to i
end repeat
xs
else
{}
end if
end enumFromTo

-- foldl :: (a -> b -> a) -> a -> [b] -> a
on foldl(f, startValue, xs)
tell mReturn(f)
set v to startValue
set lng to length of xs
repeat with i from 1 to lng
set v to |λ|(v, item i of xs, i, xs)
end repeat
return v
end tell
end foldl

-- justifyRight :: Int -> Char -> String -> String
on justifyRight(n, cFiller)
script
on |λ|(s)
if n > length of s then
text -n thru -1 of ((replicate(n, cFiller) as text) & s)
else
s
end if
end |λ|
end script
end justifyRight

-- mReturn :: First-class m => (a -> b) -> m (a -> b)
on mReturn(f)
-- 2nd class handler function lifted into 1st class script wrapper.
if script is class of f then
f
else
script
property |λ| : f
end script
end if
end mReturn

-- map :: (a -> b) -> [a] -> [b]
on map(f, xs)
-- The list obtained by applying f
-- to each element of xs.
tell mReturn(f)
set lng to length of xs
set lst to {}
repeat with i from 1 to lng
set end of lst to |λ|(item i of xs, i, xs)
end repeat
return lst
end tell
end map

-- max :: Ord a => a -> a -> a
on max(x, y)
if x > y then
x
else
y
end if
end max

-- unlines :: [String] -> String
on unlines(xs)
-- A single string formed by the intercalation
-- of a list of strings with the newline character.
set {dlm, my text item delimiters} to ¬
{my text item delimiters, linefeed}
set s to xs as text
set my text item delimiters to dlm
s
end unlines

-- unwords :: [String] -> String
on unwords(xs)
set {dlm, my text item delimiters} to ¬
{my text item delimiters, space}
set s to xs as text
set my text item delimiters to dlm
return s
end unwords
```
Output:
```1

1 1
1 1

1 1 1
1 0 1
1 1 1

1 1 1 1
1 0 0 1
1 0 0 1
1 1 1 1

1 1 1 1 1
1 0 0 0 1
1 0 0 0 1
1 0 0 0 1
1 1 1 1 1

1 1 1 1 1 1
1 0 0 0 0 1
1 0 0 0 0 1
1 0 0 0 0 1
1 0 0 0 0 1
1 1 1 1 1 1
```

## Arturo

```drawSquare: function [side][
loop 1..side 'x ->
print map 1..side 'y [
(any? @[x=1 y=1 x=side y=side])? -> 1 -> 0
]
]

drawSquare 4
print ""
drawSquare 6
```
Output:
```1 1 1 1
1 0 0 1
1 0 0 1
1 1 1 1

1 1 1 1 1 1
1 0 0 0 0 1
1 0 0 0 0 1
1 0 0 0 0 1
1 0 0 0 0 1
1 1 1 1 1 1```

## AWK

```# syntax: GAWK -f FOUR_SIDES_OF_SQUARE.AWK
BEGIN {
for (n=6; n<=7; n++) {
for (i=1; i<=n; i++) {
for (j=1; j<=n; j++) {
tmp = (i==1 || i==n || j==1 || j==n) ? 1 : 0
printf("%2d",tmp)
}
printf("\n")
}
print("")
}
exit(0)
}
```
Output:
``` 1 1 1 1 1 1
1 0 0 0 0 1
1 0 0 0 0 1
1 0 0 0 0 1
1 0 0 0 0 1
1 1 1 1 1 1

1 1 1 1 1 1 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 1 1 1 1 1 1
```

## BQN

```Square ← ∨⌜˜1⌽↑⟜1‿1

Square 5
```
Output:
```┌─
╵ 1 1 1 1 1
1 0 0 0 1
1 0 0 0 1
1 0 0 0 1
1 1 1 1 1
┘```

## C

```#include <stdio.h>

void hollowMatrix(unsigned int n) {
int i, j;
for (i = 0; i < n; ++i) {
for (j = 0; j < n; ++j) {
if (i == 0 || i == n - 1 || j == 0 || j == n - 1) {
printf("%d ", 1);
} else {
printf("%d ", 0);
}
}
printf("\n");
}
}

int main() {
hollowMatrix(10);
printf("\n");
hollowMatrix(11);
return 0;
}
```
Output:
```1 1 1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 1 1 1 1 1 1 1 1 1

1 1 1 1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 0 1
1 1 1 1 1 1 1 1 1 1 1
```

## C++

```#include <concepts>
#include <iostream>

// Print each element of a matrix according to a predicate.  It
// will print a '1' if the predicate function is true, otherwise '0'.
void PrintMatrix(std::predicate<int, int, int> auto f, int size)
{
for(int y = 0; y < size; y++)
{
for(int x = 0; x < size; x++)
{
std::cout << " " << f(x, y, size);
}
std::cout << "\n";
}
std::cout << "\n";
}

int main()
{
// a lambda to show the sides
auto fourSides = [](int x, int y, int size)
{
return x == 0 || (y == 0) || (x == size - 1) || (y == size - 1);
};

PrintMatrix(fourSides, 8);
PrintMatrix(fourSides, 9);
}
```
Output:
``` 1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 1
1 1 1 1 1 1 1 1

1 1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 1 1 1 1 1 1 1 1
```

## Delphi

Works with: Delphi version 6.0

```procedure FillSquare(Memo: TMemo; Size: integer);
var X,Y: integer;
var S: string;
begin
S:='';
for Y:=1 to Size do
begin
for X:=1 to Size do
begin
if (X=1) or (X=Size) or
(Y=1) or (Y=Size) then S:=S+' 1'
else S:=S+' 0';
end;
S:=S+#\$0D#\$0A;
end;
end;

procedure ShowFillSquare(Memo: TMemo);
begin
FillSquare(Memo, 6);
FillSquare(Memo, 7);
end;
```
Output:
``` 1 1 1 1 1 1
1 0 0 0 0 1
1 0 0 0 0 1
1 0 0 0 0 1
1 0 0 0 0 1
1 1 1 1 1 1

1 1 1 1 1 1 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 1 1 1 1 1 1
```

## F#

```// Four sides of square. Nigel Galloway: February 18th., 2022
let m11 m=Array2D.init m m (fun n g->if n=0 || g=0 || g=m-1 || n=m-1 then 1 else 0)
printfn "%A\n\n%A" (m11 5) (m11 6)
```
Output:
```[[1; 1; 1; 1; 1]
[1; 0; 0; 0; 1]
[1; 0; 0; 0; 1]
[1; 0; 0; 0; 1]
[1; 1; 1; 1; 1]]

[[1; 1; 1; 1; 1; 1]
[1; 0; 0; 0; 0; 1]
[1; 0; 0; 0; 0; 1]
[1; 0; 0; 0; 0; 1]
[1; 0; 0; 0; 0; 1]
[1; 1; 1; 1; 1; 1]]
```

## FreeBASIC

### Text based

```Sub hollowMatrix(n As Integer)
For i As Integer = 0 To n
For j As Integer = 0 To n
Print Iif((i = 0) Or (i = n) Or (j = 0) Or (j = n), "1 ", "0 ");
Next j
Print
Next i
End Sub

hollowMatrix(9)
Sleep```
Output:
```1 1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 1 1 1 1 1 1 1 1 ```

### Graphical

```Dim As Integer n = 9, size = 60 * n + 70
Screenres size, size, 24
Cls
Windowtitle "Four sides of square"

Dim As Integer beige = Rgb(245, 245, 220), brown = Rgb(171, 82, 54)

For x As Integer = 0 To n
For y As Integer = 0 To n
Dim As Integer cx = x*60 + 10
Dim As Integer cy = y*60 + 10
If (x = 0) Or (x = n) Or (y = 0) Or (y = n) Then
Line (cx,cy) - (cx+50, cy+50), brown, BF
Draw String (cx + 22, cy + 22), "1", 0
Else
Line (cx,cy) - (cx+50, cy+50), beige, BF
Draw String (cx + 22, cy + 22), "0", 0
End If
Next y
Next x
Bsave "hollowMatrix.bmp",0
Sleep```
Output:

## Go

```package main

import "fmt"

func hollowMatrix(n uint) {
for i := uint(0); i < n; i++ {
for j := uint(0); j < n; j++ {
if i == 0 || i == n-1 || j == 0 || j == n-1 {
fmt.Printf("%d ", 1)
} else {
fmt.Printf("%d ", 0)
}
}
fmt.Println()
}
}

func main() {
hollowMatrix(8)
fmt.Println()
hollowMatrix(9)
}
```
Output:
```1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 1
1 1 1 1 1 1 1 1

1 1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 1 1 1 1 1 1 1 1
```

```import Data.List (intercalate, intersperse)
import Data.List.Split (chunksOf)
import System.Environment (getArgs)

-- An n by n square of characters, having 1s on the borders and 0s in the
-- interior.  We assume n ≥ 0.
square :: Int -> String
square n = intercalate "\n" \$ map (intersperse ' ') \$ chunksOf n sq
where sq = [sqChar r c | r <- [0..n-1], c <- [0..n-1]]
sqChar r c = if isBorder r c then '1' else '0'
isBorder r c = r == 0 || r == n-1 || c == 0 || c == n-1

main :: IO ()
main = do
sizes <- map read <\$> getArgs
putStrLn \$ intercalate "\n\n" \$ map square sizes
```
Output:
```\$ four_sides 0 1 2 3 4 5

1

1 1
1 1

1 1 1
1 0 1
1 1 1

1 1 1 1
1 0 0 1
1 0 0 1
1 1 1 1

1 1 1 1 1
1 0 0 0 1
1 0 0 0 1
1 0 0 0 1
1 1 1 1 1```

Or, expressed in terms of Data.Matrix:

```import Data.Matrix

------------------ FOUR SIDES OF A SQUARE ----------------

fourSides :: Int -> Matrix Int
fourSides n = matrix n n
(\(i, j) -> (fromEnum . or) ((==) <\$> [1, n] <*> [i, j]))

--------------------------- TEST -------------------------
main :: IO ()
main = mapM_ print \$ fourSides <\$> [0 .. 5]
```
Output:
```┌  ┐
└  ┘
┌   ┐
│ 1 │
└   ┘
┌     ┐
│ 1 1 │
│ 1 1 │
└     ┘
┌       ┐
│ 1 1 1 │
│ 1 0 1 │
│ 1 1 1 │
└       ┘
┌         ┐
│ 1 1 1 1 │
│ 1 0 0 1 │
│ 1 0 0 1 │
│ 1 1 1 1 │
└         ┘
┌           ┐
│ 1 1 1 1 1 │
│ 1 0 0 0 1 │
│ 1 0 0 0 1 │
│ 1 0 0 0 1 │
│ 1 1 1 1 1 │
└           ┘```

## J

Implementation:

```fsosq=: {{+./~(+.|.)y{.1}}
```

Some examples:

```   fsosq 0
fsosq 1
1
fsosq 2
1 1
1 1
fsosq 3
1 1 1
1 0 1
1 1 1
fsosq 4
1 1 1 1
1 0 0 1
1 0 0 1
1 1 1 1
fsosq 10
1 1 1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 1 1 1 1 1 1 1 1 1
```

Gui examples are not visible here, but, for example:

```   require'viewmat'
viewmat fsosq 20
viewmat fsosq 5
```

## jq

Works with: jq

Works with gojq, the Go implementation of jq

```def square_perimeter_matrix:
[range(0; .) | 1] as \$top
| [1, (range(0; .-2) | 0), 1] as \$two
| [\$top, (range(0; .-2)|\$two), \$top];

def display:
map(join(" ")) | join("\n");```

Example:

`9|square_perimeter_matrix|display`
Output:
```1 1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 1 1 1 1 1 1 1 1
```

## Julia

Gtk graphical version.

```using Gtk

function set_gtk_style!(widget::Gtk.GtkWidget, style::String, value::Int)
sc = Gtk.GAccessor.style_context(widget)
pr = Gtk.CssProviderLeaf(data=" button {\$style}")
push!(sc, Gtk.StyleProvider(pr), value)
end

function squareonesapp(N)
win = GtkWindow("Ones Square", 700, 700)
grid = GtkGrid()
buttons = [GtkButton(i == 1 || j == 1 || i == N || j == N ? " 1 " : " 0 ") for i in 1:N, j in 1:N]
for i in 1:N, j in 1:N
grid[i, j] = buttons[i, j]
set_gtk_property!(buttons[i, j], :expand, true)
c = i == 1 || j == 1 || i == N || j == N ? "red" : "navy"
set_gtk_style!(buttons[i, j], " font-size: 32px; background-color: \$c ; ", 600)
end
push!(win, grid)
condition = Condition()
endit(w) = notify(condition)
signal_connect(endit, win, :destroy)
showall(win)
wait(condition)
end

squareonesapp(8)
```

## Mathematica/Wolfram Language

```Manipulate[ArrayPad[ConstantArray[0, {1, 1} n - 1], 1, 1] // Grid, {n, 2, 20, 1}]
```

## Maxima

```/* Function that returns a square matrix with square pattern in  their entries */
square(n):=genmatrix(lambda([x,y],if x=1 or y=1 or x=n or y=n then 1 else 0),n,n)\$

/* Example */
square(6);
```
Output:
```matrix(
[1,	1,	1,	1,	1,	1],
[1,	0,	0,	0,	0,	1],
[1,	0,	0,	0,	0,	1],
[1,	0,	0,	0,	0,	1],
[1,	0,	0,	0,	0,	1],
[1,	1,	1,	1,	1,	1]
)
```

## Nim

There are several ways to draw the square. Here is one of them:

```import std/[sequtils, strutils]

proc drawSquare(n: Positive) =
let s1 = repeat(1, n).join(" ")
let s2 = (1 & repeat(0, n - 2) & 1).join(" ")
echo s1
for i in 2..<n: echo s2
echo s1

drawSquare(7)
```
Output:
```1 1 1 1 1 1 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 1 1 1 1 1 1
```

## Perl

```use strict;
use warnings;
use feature 'say';

my \$n = 5;
say join ' ', @\$_ for ([(1)x\$n], (map { [1, (0)x(\$n-2), 1] } 0..\$n-3), [(1)x\$n]);
```
Output:
```1 1 1 1 1
1 0 0 0 1
1 0 0 0 1
1 0 0 0 1
1 1 1 1 1```

## Phix

See Matrix_with_two_diagonals#Phix and press 'O'.

## PL/M

Works with: 8080 PL/M Compiler
... under CP/M (or an emulator)
```100H: /* DRAW SOME SQUARES WITH 1S ON THE EDGES and 0S ELSEWHERE             */

/* CP/M SYSTEM CALL AND I/O ROUTINES                                      */
BDOS:      PROCEDURE( FN, ARG ); DECLARE FN BYTE, ARG ADDRESS; GOTO 5; END;
PR\$CHAR:   PROCEDURE( C ); DECLARE C BYTE;    CALL BDOS( 2, C );  END;
PR\$NL:     PROCEDURE;   CALL PR\$CHAR( 0DH ); CALL PR\$CHAR( 0AH ); END;

DRAW\$SQUARE: PROCEDURE( N );
DECLARE N BYTE;
DECLARE ( I, J ) BYTE;
DO I = 1 TO N;
DO J = 1 TO N;
CALL PR\$CHAR( ' ' );
IF I = 1 OR I = N OR J = 1 OR J = N THEN CALL PR\$CHAR( '1' );
ELSE CALL PR\$CHAR( '0' );
END;
CALL PR\$NL;
END;
END DRAW\$SQUARE ;

CALL DRAW\$SQUARE( 6 );
CALL PR\$NL;
CALL DRAW\$SQUARE( 7 );

EOF```
Output:
``` 1 1 1 1 1 1
1 0 0 0 0 1
1 0 0 0 0 1
1 0 0 0 0 1
1 0 0 0 0 1
1 1 1 1 1 1

1 1 1 1 1 1 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 1 1 1 1 1 1
```

## Processing

```//Aamrun, 27th June 2022

size(1000,1000);

textSize(50);

for(int i=0;i<10;i++){
for(int j=0;j<10;j++){
noFill();
square(i*100,j*100,100);
fill(#000000);
if(i==0||i==9||j==0||j==9){
text("1",i*100+50,j*100+50);
}
else{
text("0",i*100+50,j*100+50);
}
}
}
```

## Python

### Procedural

```size = 9
for row in range(size):
for col in range(size):
if row == 0 or row == size-1 or col == 0 or col == size-1:
print("1", end=" ")
else:
print("0", end=" ")
print()
```
Output:

See Raku output.

### Elaborate procedural

The following version illustrates several features of Python, such as default arguments, nested functions with lexical scoping, generators, and convenient syntax for creating sets and performing set operations such as intersection.

```def square(size=9):

def is_at_border(row, col):
# `&` is set intersection: if the set {row, col} intersects the set
# {0, size-1}, then at least one of (row, col) is either 0 or size-1
return {row, col} & {0, size-1}

for row in range(size):
print(' '.join(
'1' if is_at_border(row, col) else '0'
for col in range(size)
))

suqare()
```

### Functional

```'''Four sides of a square'''

# fourSides :: Int -> [[Int]]
def fourSides(n):
'''A square grid with ones in all edge values
and zeros elsewhere.
'''
edge = [1, n]
return matrix(
n, n, lambda row, col: int(
row in edge or col in edge
)
)

# ------------------------- TEST -------------------------
# main :: IO ()
def main():
'''Square grids of dimension 7 and 10'''
for n in [7, 10]:
print(
showMatrix(
fourSides(n)
) + '\n'
)

# ----------------------- GENERIC ------------------------

# matrix :: Int -> Int -> ((Int, Int) -> a) -> [[a]]
def matrix(nRows, nCols, f):
'''A matrix of a given number of columns and rows,
in which each value is a given function over the
tuple of its (one-based) row and column indices.
'''
return [
[f(y, x) for x in range(1, 1 + nCols)]
for y in range(1, 1 + nRows)
]

# showMatrix :: [[a]] -> String
def showMatrix(rows):
'''String representation of a matrix'''
return '\n'.join([
' '.join([str(x) for x in y]) for y in rows
])

# MAIN ---
if __name__ == '__main__':
main()
```
Output:
```1 1 1 1 1 1 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 1 1 1 1 1 1

1 1 1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 1 1 1 1 1 1 1 1 1```

## Quackery

```  [ 0 over 2 - of
1 tuck join join nested
over 2 - of
1 rot of
nested tuck join join ] is four-sides ( n --> [ )

8 four-sides
witheach
[ witheach [ echo sp ] cr ]
cr
9 four-sides
witheach
[ witheach [ echo sp ] cr ]```
Output:
```1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 1
1 1 1 1 1 1 1 1

1 1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 1 1 1 1 1 1 1 1
```

## Raku

This isn't a matrix, especially if it is supposed to be graphical; it's a very small (or extremely low resolution) bitmap.

```sub hollow (\$n) { [1 xx \$n], |(0 ^..^ \$n).map( { [flat 1, 0 xx \$n - 2, 1] } ), [1 xx \$n] }

.put for hollow 7;
put '';
.put for hollow 10;
```
Output:
```1 1 1 1 1 1 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 1 1 1 1 1 1

1 1 1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 0 1
1 1 1 1 1 1 1 1 1 1```

## Red

```Red[]

view-square: function [size][
matrix: copy [
title "Four sides of a square"
style cell: base 50x50 font-size 20
style one: cell brown font-color beige "1"  ; I am not an artist. Please have mercy!
style zero: cell beige font-color brown "0"
]
repeat i size [
either any [i = 1 i = size] [
append matrix append/dup copy [] 'one size
][
row: append/dup copy [] 'zero size
row/1: row/:size: 'one
append matrix row
]
append matrix 'return
]
view matrix
]

view-square 9
```
Output:

## Ring

```# Project : Identity Matrix
# Date    : 2022/16/02
# Author  : Gal Zsolt (~ CalmoSoft ~)
# Email   : <calmosoft@gmail.com>

size = 9
C_Spacing = 1

Button = newlist(size,size)
LayoutButtonRow = list(size)

app = new qApp
{
win = new qWidget() {
setWindowTitle('Identity Matrix')
move(500,100)
reSize(600,600)
winheight = win.height()
fontSize = 18 + (winheight / 100)

LayoutButtonMain = new QVBoxLayout()
LayoutButtonMain.setSpacing(C_Spacing)
LayoutButtonMain.setContentsmargins(0,0,0,0)

for Row = 1 to size
LayoutButtonRow[Row] = new QHBoxLayout() {
setSpacing(C_Spacing)
setContentsmargins(0,0,0,0)
}
for Col = 1 to size
Button[Row][Col] = new QPushButton(win) {
setSizePolicy(1,1)
}

next
next
LayoutDataRow1 = new QHBoxLayout() { setSpacing(C_Spacing) setContentsMargins(0,0,0,0) }
setLayout(LayoutButtonMain)
show()
}
pBegin()
exec()
}

func pBegin()
for Row = 1 to size
for Col = 1 to size
if Row = 1 or row = size or Col = 1 or Col = size
Button[Row][Col].setStyleSheet(C_ButtonOrangeStyle)
Button[Row][Col].settext("1")
else
Button[Row][Col].setStyleSheet(C_ButtonBlueStyle)
Button[Row][Col].settext("0")
ok
next
next```

Output image:
Four sides of square

## RPL

```≪ → n
≪ "" 1 n START "1 " + NEXT DUP
2 n 1 - START
"" 1 n FOR j j 1 == j n == OR →STR + " " + NEXT NEXT
n ROLL 1 n FOR j j DISP NEXT
```
```4 TASK
```
Output:
```1 1 1 1
1 0 0 1
1 0 0 1
1 1 1 1
```

## Ruby

```def square_sides(size = 9)
Array.new(size){|n| n==0 || n==size-1 ? [1]*size : [1]+[0]*(size-2)+[1]}
end

puts square_sides.map{|line| line.join (" ") }
```
Output:
```1 1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 1 1 1 1 1 1 1 1
```

## Sidef

```var n = 5

[n.of(1), (n-2).of([1, (n-2).of(0)..., 1])..., n.of(1)].each {|row|
say row.join(' ')
}
```
Output:
```1 1 1 1 1
1 0 0 0 1
1 0 0 0 1
1 0 0 0 1
1 1 1 1 1
```

## Wren

### Text based

```var hollowMatrix = Fn.new { |n|
for (i in 0...n) {
for (j in 0...n) {
System.write((i == 0 || i == n-1 || j == 0 || j == n-1) ? "1 " : "0 ")
}
System.print()
}
}

hollowMatrix.call(9)
```
Output:
```1 1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0 1
1 1 1 1 1 1 1 1 1
```

### Graphical

Library: DOME
Library: Go-fonts

This is designed to look as close as possible to the Red entry's image so that we don't have to fill up Wikimedia Commons with similar looking images.

```import "dome" for Window
import "graphics" for Canvas, Color, Font
class Main {
construct new(n) {
var size = 60 * n + 10
Window.resize(size, size)
Canvas.resize(size, size)
Window.title = "Four sides of a square"
// see Go-fonts page
Canvas.font = "Go-Regular20"
var beige = Color.new(245, 245, 220)
Canvas.cls(Color.lightgray)
for (x in 0...n) {
for (y in 0...n) {
var cx = x*60 + 10
var cy = y*60 + 10
if (x == 0 || x == n-1 || y == 0 || y == n-1) {
Canvas.rectfill(cx, cy, 50, 50, Color.brown)
Canvas.print("1", cx + 20, cy + 15, beige)
} else {
Canvas.rectfill(cx, cy, 50, 50, beige)
Canvas.print("0", cx + 20, cy + 15, Color.brown)
}
}
}
}

init() {}

update() {}

draw(alpha) {}
}

var Game = Main.new(9)
```
Output:
```Similar to Red entry image.
```

## XPL0

```proc DrawMat(S);
int  S, I, J;
[for I:= 0 to S-1 do
[for J:= 0 to S-1 do
Text(0, if I>0 & I<S-1 & J>0 & J<S-1 then "0 " else "1 ");
CrLf(0);
];
];
[DrawMat(6);  CrLf(0);
DrawMat(7);  CrLf(0);
]```
Output:
```1 1 1 1 1 1
1 0 0 0 0 1
1 0 0 0 0 1
1 0 0 0 0 1
1 0 0 0 0 1
1 1 1 1 1 1

1 1 1 1 1 1 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 0 0 0 0 0 1
1 1 1 1 1 1 1
```