#include "stdio.h"
#include "string.h"
int main()
{
    struct stu
    {
        int sno;
        char name[10];
        char sex;
        float score;
    }student[5];
   
    int i=0,count;
    float sum=0;
    while(i<5)
    {
        printf("请输入%d个学生学号:\n",i+1);
        scanf("%d",&student[i].sno);                         //scanf会读回车进去，无法换行?
        printf("请输入学生姓名:\n");
        gets(student[i].name);
        printf("请输入学生性别:\n");
        scanf("%c",&student[i].sex);
        printf("请输入学生成绩:\n");
        scanf("%f",&student[i].score);
        if(student[i].score<60.0)
            count++;
        sum=sum+student[i].score;
        i++;
    }
    printf("学号\t\t姓名\t\t性别\t\t分数\n");
    for(i=0;i<5;i++)
        printf("%d\t\t%s\t\t%c\t\t%f\n",student[i].sno,student[i].name,student[i].sex,student[i].score);
    printf("不及格人数%d\t平均成绩%f\n",count,sum/5);
    return 0;
}

1 bug_a  缓冲区问题， ‘\n’没有做过滤处理
解决方案：
while(getchar()!= '\n')
            continue;
2 bug_b  字符空间声明   char sex;
解决方案：
char sex[10];

PS：  float sum=0; 写成float sum=0.0安全一点，  

----------------------------------------------
#include "stdio.h"
#include "string.h"
int main()
{
    struct stu
    {
        int sno;
        char name[10];
        char sex[10];
        float score;
    }student[5];
   
    int i=0,count;
    float sum=0.0;
    while(i<5)
    {
        printf("请输入%d个学生学号:\n",i+1);
        scanf("%d",&student[i].sno);                         //scanf会读回车进去，无法换行?
        while(getchar()!= '\n')
            continue;
        printf("请输入学生姓名:\n");
        gets(student[i].name);
        printf("请输入学生性别:\n");
        scanf("%c",&student[i].sex);
        while(getchar()!= '\n')
            continue;
        printf("请输入学生成绩:\n");
        scanf("%f",&student[i].score);
        while(getchar()!= '\n')
            continue;
        if(student[i].score<60.0)
            count++;
        sum=sum+student[i].score;
        i++;
    }
    printf("学号\t\t姓名\t\t性别\t\t分数\n");
    for(i=0;i<5;i++)
        printf("%d\t\t%s\t\t%c\t\t%f\n",student[i].sno,student[i].name,student[i].sex,student[i].score);
    printf("不及格人数%d\t平均成绩%f\n",count,sum/5);
    return 0;
}

 for(i=0;i<5;i++)
        printf("%d\t\t%s\t\t%c\t\t%f\n",student[i].sno,student[i].name,student[i].sex,student[i].score);
    printf("不及格人数%d\t平均成绩%f\n",count,sum/5);
    return 0;
这段代码刚没细看，又发现了几个bug；

3 .bug_c 声明 int count; count没有初值
-----------------------------------------------------------------------------------------------------------
完整代码：
#include "stdio.h"
#include "string.h"
int main()
{
    struct stu
    {
        int sno;
        char name[10];
        char sex[10];
        float score;
    }student[5];
   
    int i=0,count=0;
    float sum=0;
    while(i<5)
    {
        printf("请输入%d个学生学号:\n",i+1);
        scanf("%d",&student[i].sno);                         //scanf会读回车进去，无法换行?
        while(getchar()!= '\n')
            continue;
        printf("请输入学生姓名:\n");
        gets(student[i].name);
        printf("请输入学生性别:\n");
        gets(student[i].sex);
        printf("请输入学生成绩:\n");
        scanf("%f",&student[i].score);
        while(getchar()!= '\n')
            continue;
        if(student[i].score<60.0)
            count++;
        sum=sum+student[i].score;
        i++;
    }
    printf("学号\t\t姓名\t\t性别\t\t分数\n");
    for(i=0;i<5;i++)
        printf("%d\t\t%s\t\t%s\t\t%f\n",student[i].sno,student[i].name,student[i].sex,student[i].score);
    printf("不及格人数%d\t平均成绩%f\n",count,sum/5);
    return 0;
}

输入student[i].sno之后的回车在键盘缓冲区。下一步的gets（）读取了回车，是这个意思吗？？
如果是这样，gets就不能读入姓名了吧。

bug_c已发现，bug_b是打算输入一个字符表示性别

3ku，大神！！！

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