Fact()的返回值类型

#include<stdio.h>unsigned long  Fact(unsigned int n);int main(){    int m;    do{        printf("Input m(m>0):");        scanf("%d",&m);    }while(m<0);    printf("%d!=%lu\n",m,Fact(m));    return 0;}unsigned long Fact(unsigned int n){    unsigned int i;    unsigned long result=1;    for(i=2;i<=n;i++)        result*=i;    return result;}