C语言二维数组求每个人平均成绩

Question

#include<stdio.h>
#include<math.h>
#include<stdlib.h>
void main()
{
    int i, j, sum=0;
    float average[4];
    int a[4][5]={80,84,78,81,82,  65,46,63,70,73,  87,93,95,82,88,  75,74,78,67,77};
    printf("求每个人的平均成绩\n");
    printf("\n");
    for(i=0;i<4;i++)
    {
        for(j=0;j<5;j++)
        {
            sum=sum+a[i][j];
        }
        average[i]=sum/5;
        sum=0;
    }
    printf("%.2f\t %.2f\t %.2f\t %.2f\n",average[0],average[1],average[2],average[3]);
    printf("\n");
}

为什么精确度不是小数点后两位，而是小数点后都是0了？

正确的是这样的：

Answer 1

average[i] = sum / 5.00;