用递归方法计算整数n的阶乘n！

#include<stdio.h>long Fact(int n);int main(){    int n;    long result;    printf("Input n:");    scanf("%d",&n);    result=Fact(n);    if(result==-1)        printf("n<0,data error!\n");    else        printf("%d=%ld\n",n,result);    return 0;}long Fact(int n){    if(n<0)        return -1;    else if(n==0||n==-1)        return 1;    else        return (n*Fact(n-1));}