计算结果没小数，例(7+8)/2=7

Question

#include<stdio.h>

int main()
{
    int n=0;
    int num;
    int sum=0;
    scanf("%lf",&num);
    while( num!=-1 ) {
        n++;
        sum += num;
        scanf("%d",&num);

    }
    double average;
    average=sum/n;
    printf("The average is %f.",average);


}

Answer 1

sum和n都是整数，两个整数相除是整除的意思，是不会有小数的，至少有一个是浮点数，结果才是普通的除法