为什么输出不到想要的结果（C语言）

Question

为什么输出不到想要的结果？

#include<stdio.h>
#include<string.h>
#include<math.h>
#include<conio.h>
#define M 10

struct student
{
    int num;
    int score;
};

int fun(struct student *s,int low,int high,struct student *b);

int main()
{
    int low,high;
    int i,t;
    struct student s[M];
    struct student b[M];
    printf("输入学生数据\n");
    for(i=0; i<M; i++)
    {
        scanf("%d%d",&s[i].num,&s[i].score);
    }
    printf("输入分数范围\n");
    scanf("%d%d",&low,&high);
    if ( high < low )
    {
        t=high;
        high=low;
        low=t;
     }
    fun(s,low,high,b);
    printf("符合条件的有：\n");
    do
    {
        printf("%d  %d",b[i].num,b[i].score);
        printf("\n");
        i++;
    }while(getchar()!='\0');
    return 0;
}

int fun(struct student *s,int low,int high,struct student *b)
{
    int i,j=0;
    for(i=0; i<M; i++)
    {
        if(s[i].score>low && s[i].score<=high)
        {
            b[j].num=s[i].num;
            b[j].score=s[i].score;
        }
    }
}

Answer 1

#include<stdio.h>
#include<string.h>
#include<math.h>
#include<conio.h>
#define M 10

struct student
{
    int num;
    int score;
};

int fun(struct student *s, int low, int high, struct student *b);

int main()
{
    int low, high;
    int i, t;
    struct student s[M];
    struct student b[M];
    printf("输入学生数据\n");
    for (i = 0; i < M; i++)
    {
        scanf("%d%d", &s[i].num, &s[i].score);
    }
    printf("输入分数范围\n");
    scanf("%d%d", &low, &high);
    if (high < low)
    {
        t = high;
        high = low;
        low = t;
    }
    int count = fun(s, low, high, b);
    printf("符合条件的有：\n");
    i = 0;
    do
    {
        printf("%d  %d", b[i].num, b[i].score);
        printf("\n");
        i++;
        count--;
    } while (count > 0);
    return 0;
}

int fun(struct student *s, int low, int high, struct student *b)
{
    int i, j = 0;
    for (i = 0; i < M; i++)
    {
        if (s[i].score > low && s[i].score <= high)
        {
            b[j].num = s[i].num;
            b[j].score = s[i].score;
            j++;
        }
    }
    return j;
}