怎么用C语言结构体来编写程序啊？

#include <stdio.h>

struct student
{
    int num;
    char name[20];
    int score[3];
    float avg;
};



int main()
{
    int i,j;
    struct student stu[3];
    for (i=0;i<3;i++)
    {
        scanf("%d %s",&stu[i].num,stu[i].name);
        stu[i].avg = 0;
        for(j=0;j<3;j++)
        {
            scanf("%d",&stu[i].score[j]);
            stu[i].avg += stu[i].score[j];
        }
        stu[i].avg/=3;
    }
    for(i=0;i<3;i++)
        printf("%s %f\n",stu[i].name,stu[i].avg);
    return 0;
}