Реверс массива

const
  N = 12;

var
  A: array [1..N] of integer;
  x, i: integer;

begin
  writeln('Исходный массив');

  for i := 1 to 12 do
  begin
    A[i] := random(24) - 12;
    write(A[i], '  ');
  end;

  writeln;

  for i := 1 to 2 do
  begin
    x := A[i];
    A[i] := A[5 - i];
    A[5 - i] := x;
  end;

  for i := 5 to 6 do
  begin
    x := A[i];
    A[i] := A[13 - i];
    A[13 - i] := x;
  end;

  for i := 9 to 10 do
  begin
    x := a[i];
    A[i] := A[21 - i];
    A[21 - i] := x;
  end;

  writeln('Преобразованный массив');

  for i := 1 to 12 do
    write(a[i], '  ');
end.