#include<stdio.h>
#include<conio.h>
int fact(int num);  //function prototype declaration
int main()
{
    int n, fac;
    printf("Enter an integer: ");
    scanf("%d", &n);

    fac = fact(n); //function call

    printf("The factorial of %d is %d", n, fac);

}

//factorial function
int fact(int num)   //function definition
{
    int res;

    res = num;
    while(num>1)
    {
        res = res*(num-1);
        num = num-1;
    }
    return res;
}