n个非负整数的统计

#include<iostream>
using namespace std;
int main(){
    int a,fmin,fmax,num,sum,product,average,i;
    sum=0;
    num=0;
    product=1;
part1:
    scanf("%d",&a);
    if(a==-1)
      goto part2;
    i=a;
    sum+=a;
    num++;
    product*=a;
    if(num<2){
      fmin=a;
      fmax=a;
    }
    if(num>1){
      fmin=min(i,fmin);
      fmax=max(i,fmax);
    }
    goto part1;
 part2:
        printf("Sum is %d\n",sum);
        average=sum/num;
        printf("Average is %d\n",average);
        printf("Product is %d\n",product);
        printf("Smallest is %d\n",fmin);
        printf("Largest is %d\n",fmax);
}