/* Bai tap 3_1 - Ham tinh N! */

#include <stdio.h>

unsigned long giaithua(int n)

{

   unsigned long ketqua = 1;

   for (i=2; i<=n; i++)

     ketqua *= i;

   return ketqua;

}

void main()

{

  printf("

Nhap vao gia tri N : ");

  scanf("%d", &n);

  printf("%d! = %lu", n, giaithua(n));

  getch();

}