题解 | #n的阶乘#

#include <stdio.h>

long int factorial(int n){
    long int res=1;
    for(int i=n;i>=1;i--)  res *=i;
    return res;
}

int main(){
    int n;
    while (scanf("%d",&n)==1) printf("%ld\n",factorial(n));
    return 0;
}