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

#include <stdio.h>

unsigned long giaithua(int n)

{

unsigned long ketqua = 1;

int i;

for (i=2; i<=n; i++)

ketqua *= i;

return ketqua;

}

void main()

{

int n;

printf("

Nhap vao gia tri N : ");

scanf("%d", &n);

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

getch();

}