Hàm:

program giai_thua;

uses crt;

var n:integer;

{---Ham---}

function gt(a:integer):longint;

var i:integer;

begin

      gt:=1;

      for i:=1 to a do gt:=gt*i;

end;

{---Chuong-trinh-chinh---}

BEGIN

      clrscr;

      write('Nhap so: ');  readln(n);

      write(n,'! = ',gt(n));

      readln;

end.

Thủ tục:

program giai_thua;

uses crt;

var n,gt:integer;

{---Thu-tuc---}

procedure giaithua(a:integer);

var i:integer;

begin

      gt:=1;

      for i:=1 to a do gt:=gt*i;

end;

{---Chuong-trinh-chinh---}

BEGIN

      clrscr;

      write('Nhap so: ');  readln(n);

      giaithua(n);

      write(n,'! = ',gt);

      readln;

end.

a) Hàm:

var n: integer;

function gt(a:integer):longint;

var i: integer;

begin

      gt:=1;

      for i:=1 to a do gt:=gt*i;

end;

Begin

      write('Nhap so: ');  readln(n);

      write(n, '! = ', gt(n));

      readln

end.

b)Thủ tục:

var n, gt: integer;

procedure giaithua(a:integer);

var i:integer;

begin

      gt:=1;

      for i:=1 to a do gt:=gt*i;

end;

Begin

      write('Nhap so: ');  readln(n);

      giaithua(n);

      write(n, '! = ', gt);

      readln

end.