计算N的阶乘
#include <iostream>
using namespace std;
int main()
{
int a[1024] = {0};
int n = 0;
while (scanf("%d",&n) == 1){
memset(a, 0, sizeof(a));
a[0] = 1;//代表从1开始乘
int k = 1000;
for (int i = 2; i <= n; ++i){
int c = 0;//进位
for (int j = 0; j < k; ++j){
int s = a[j] * i + c;
a[j] = s % 10;
c = s / 10;
}
}
while (k > 0 && a[k] == 0)
k--;
for (int i = k; i >= 0; --i)
printf("%d",a[i]);
printf("\n");
}
return 0;
}