Переставить блоки в матрице

const maxn = 20 ; var a : array [0 .. maxn * 2 , 0 .. maxn * 2] of Integer ; n :
Integer; procedure init; var r, c : Integer; begin ReadLn(n) ; for r := 0 to n *
2 - 1 do for c := 0 to n * 2 - 1 do a[r, c] := r * n * 2 + c; end; procedure out
; var r, c : Integer; begin for r := 0 to n * 2 - 1 do begin for c := 0 to n * 2
- 1 do Write(a[r, c] : 5); WriteLn; end; end; procedure swap(var a, b : Integer)
; begin a := a + b; b := a - b ; a := a - b ; end ; procedure hswap ; var r, c :
Integer; begin for r := 0 to n * 2 - 1 do for c := 0 to n-1 do swap(a[r, c], a[r
, c + n]); end; procedure vswap ; var r, c : Integer ; begin for r := 0 to n - 1
do for c := 0 to n * 2 - 1 do swap(a[r, c], a[r + n, c]); end; begin Randomize ;
init; WriteLn('исходная матрица'); out; hswap; vswap; WriteLn('новая матрица') ;
out; end.

const
  n = 3;
var
  a: array[1..2*n, 1..2*n] of real;
  i, j: integer;
  t: real;
begin
  randomize;
  writeln('Source matrix:');
  for i := 1 to 2 * n do
    begin
      for j := 1 to 2 * n do
        begin
          a[i,j] := random * 200 - 100;
          write(a[i,j]:7:2)
        end;
      writeln
    end;
  for i := 1 to n do
    for j := 1 to n do
      begin
        t := a[i,j];
        a[i,j] := a[i+n,j+n];
        a[i+n,j+n] := t;
        t := a[i,j+n];
        a[i,j+n] := a[i+n,j];
        a[i+n,j] := t
      end;
  writeln('Modified matrix:');
  for i := 1 to 2 * n do
    begin
      for j := 1 to 2 * n do write(a[i,j]:7:2);
      writeln
    end;
  readln
end.