program ArrayExample;

uses
  SysUtils;

var
  a: array[0..4] of Integer;
  b: array[0..4] of Integer;
  twoD: array[0..1, 0..2] of Integer;
  i, j: Integer;

begin
  // By default, an array is zero-valued, which for Integers means 0s.
  WriteLn('emp: ', '[', a[0], ' ', a[1], ' ', a[2], ' ', a[3], ' ', a[4], ']');

  // We can set a value at an index using the array[index] := value syntax,
  // and get a value with array[index].
  a[4] := 100;
  WriteLn('set: ', '[', a[0], ' ', a[1], ' ', a[2], ' ', a[3], ' ', a[4], ']');
  WriteLn('get: ', a[4]);

  // The Length function returns the length of an array.
  WriteLn('len: ', Length(a));

  // Use this syntax to declare and initialize an array in one line.
  b := [1, 2, 3, 4, 5];
  WriteLn('dcl: ', '[', b[0], ' ', b[1], ' ', b[2], ' ', b[3], ' ', b[4], ']');

  // In Pascal, we can't have the compiler count the number of elements for us,
  // so we need to specify the size explicitly.

  // In Pascal, we can't specify indexes like in Go, but we can initialize
  // specific elements and leave others as default.
  b[0] := 100;
  b[3] := 400;
  b[4] := 500;
  WriteLn('idx: ', '[', b[0], ' ', b[1], ' ', b[2], ' ', b[3], ' ', b[4], ']');

  // Array types are one-dimensional, but you can create multi-dimensional arrays.
  for i := 0 to 1 do
    for j := 0 to 2 do
      twoD[i, j] := i + j;

  Write('2d: ');
  for i := 0 to 1 do
  begin
    Write('[');
    for j := 0 to 2 do
    begin
      Write(twoD[i, j]);
      if j < 2 then Write(' ');
    end;
    Write(']');
    if i = 0 then Write(' ');
  end;
  WriteLn;

  // You can create and initialize multi-dimensional arrays at declaration.
  twoD := ((1, 2, 3), (1, 2, 3));
  Write('2d: ');
  for i := 0 to 1 do
  begin
    Write('[');
    for j := 0 to 2 do
    begin
      Write(twoD[i, j]);
      if j < 2 then Write(' ');
    end;
    Write(']');
    if i = 0 then Write(' ');
  end;
  WriteLn;
end.

$ fpc arrays.pas
$ ./arrays
emp: [0 0 0 0 0]
set: [0 0 0 0 100]
get: 100
len: 5
dcl: [1 2 3 4 5]
idx: [100 0 0 400 500]
2d: [0 1 2] [1 2 3]
2d: [1 2 3] [1 2 3]