新手，想问问这个程序哪里出错了？

Question

 #include<stdio.h>
int main()
{
    int s,i,num=1,sum=0,max,min;
    float avg;
    printf("Input data:");
    scanf("%d",&s);
    if(s==-1)
    {
    printf("Input Error!");
    return 0;
    }
    else
    {
    max=s;
    min=s;
    sum=s;
    }
    while(scanf("%d",&s),s!=-1) 
     {
      if (max<s) max=s;
      if (min>s) min=s;
      sum=sum+s;
      num++;
      }

     avg=sum/num;
     printf("num=%d,max=%d,min=%d,avg=%.2f",num,max,min,avg);
     return 0;

}

Answer 1

avg=sum/(float)num;