Question

How to print a given matrix in spiral form with Pascal

Answer 1

program SpiralMatrix;

type
  TMatrix = array[0..3, 0..3] of Integer;

procedure PrintMatrixInSpiralForm(matrix: TMatrix);
var
  top, bottom, left, right, i: Integer;
begin
  if Length(matrix) = 0 then Exit;

  top := 0;
  bottom := High(matrix);
  left := 0;
  right := High(matrix[0]);

  while True do
  begin
    if left > right then Break;

    // Top row
    for i := left to right do
      Write(matrix[top][i], ' ');
    Writeln;
    Inc(top);

    if top > bottom then Break;

    // Right column
    for i := top to bottom do
      Write(matrix[i][right], ' ');
    Writeln;
    Dec(right);

    if left > right then Break;

    // Bottom row
    for i := right downto left do
      Write(matrix[bottom][i], ' ');
    Writeln;
    Dec(bottom);

    if top > bottom then Break;

    // Left column
    for i := bottom downto top do
      Write(matrix[i][left], ' ');
    Writeln;
    Inc(left);
  end;
end;

var
  // Define the matrix
  Matrix: TMatrix = (
    (1, 2, 3, 4),
    (5, 6, 7, 8),
    (9, 10, 11, 12),
    (13, 14, 15, 16)
  );

begin

  // Print the matrix in spiral order
  PrintMatrixInSpiralForm(Matrix);
end.

 
 
(*
run:

1 2 3 4 
8 12 16 
15 14 13 
9 5 
6 7 
11 
10 

*)  

 

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