求n的阶乘以及前n个数的阶乘和
//求n的阶乘
#include<stdio.h>
#include<stdlib.h>
intmain()
{
int
n = 0;
int
sum = 1;
scanf("%d", &n);
while
(n) //n如果为零，则不进入循环体，输出的sum初始值就是1
{
sum *=n;
n--;
}
printf("%d\n", sum);
system("pause");
return
0;
}
//求从1到n的阶乘和
#include<stdio.h>
#include<stdlib.h>
intmain()
{
int
n = 0;
int
ret = 1;
int
sum = 0;
scanf("%d", &n);
for
(int
i = 1; i <=n;i++)
{
ret *= i; //ret是一直没有释放，从1的阶乘变到n的阶乘
sum += ret;
}
printf("%d\n",sum);
system("pause");
return
0;
}
