求平均值

#include<stdio.h>
int main()
{
  int number;
  int sum = 0;
  int count = 0;
  scanf("%d",&number);
  while(number!=-1){
    sum+=number;
    count++;
    scanf("%d",&number);
  }
  printf("%f\n",1.0*sum/count);
  return 0;
}