题解 | #n的阶乘#

#include<stdio.h>
int main(){
   int n;
   while(scanf("%d",&n)!=EOF && n>=0 &&n<=20)
   { int i;
     long sum=1;
     for(i=1;i<=n;i++)
       sum=sum*i;
     printf("%ld\n",sum);
   }
return 0;
}