阶乘和

采用递归和非递归实现阶乘，并计算和

#include<stdio.h>long factorial(int n);long factorial2(int n);//non-recursivelong sumOfFac(int n);int main(){int n;int i; printf("input:");scanf("%d",&n);for(i = 1;i <= n;i ++){printf("%d ! = %ld\n",i,factorial(i));}printf("sum of factorial 1 - %d: %ld",n,sumOfFac(n));return 0;}long factorial(int n){if(n == 1){return 1;}else{return n * factorial(n - 1);}}long factorial2(int n){int i;long result = 1;for(i = 1;i <= n;i ++){result *= i;}        return result;}long sumOfFac(int n){int i;long sum = 0;for(i = 1;i <= n;i++){sum += factorial(i);}return sum;}