阶乘求和(数组)

解题思路:

注意事项:

参考代码:

#include<stdio.h>

int main()

{

long long int n,sn=0;

scanf("%lld", &n);

long long int a[20] = { 1 };

int i = 0,j=1;

for (i = 1; i <= n; i++)

{

for (j = 1,a[i]=1; j <= i; j++)

{

a[i] = a[i] * j;

}

sn = sn + a[i];

}

printf("%lld", sn);

return 0;

}