vc6.0可以运行，但好多错误。。。
哪位大神帮忙修改一下
我已经改的自己都不认识自己了
#include <stdio.h>
#define M 50
struct student
{
long num;  
char name[10];  
int chinese,english,math,sum,average;      
};  
void new_student(struct student students[]);  
void search_student(struct student students[],int num);
void row_student(struct student students[]);  
void delete_student(struct student students[],int num);
void modify_student(struct student students[],int num);
int count=0;   
main()  
{
    int choice,num;  
    struct student students[M];
    printf("╔══════学生成绩管理系统══════╗\n");   
    printf("║                                        ║\n");
    printf("║                                        ║\n");
    printf("║      1.录入             2.查找         ║\n");
    printf("║                                        ║\n");
    printf("║      3.排名             4.删除         ║\n");
    printf("║                                        ║\n");
    printf("║      5.修改             0.退出         ║\n");
    printf("║                                        ║\n");
    printf("╚════════════════════╝\n");
    printf("\n");
do
{  
    printf("  *   1：输入   2：查询  3：排序   4：删除    0：退出     *\n");
    scanf("%d",&choice);
    switch(choice)
{
    case 1:
        new_student(students);
        break;         
    case 2:
        printf("请输入查询学生的学号:");
        scanf("%d",&num);
        search_student(students,num);
        break;  
    case 3:
        row_student(students);
        break;         
    case 4:
        printf("请输入要删除学生的学号:");
        scanf("%d",&num);
        delete_student(students,num);
        break;
    case 5:
        printf("请输入要修改的学生学号:");
        scanf("%d",&num);
        modify_student(students,num);
    case 0:
        break;
    default :
    printf("输入有误，请重新选择\n");
    break;
    }
}
while(choice!=0);   
printf("结束\n");
return 0;
}
/*插入*/
void new_student(struct student students[])
{  
    struct student s;
    if(count==M){
    printf("已满\n");
    return;
    }
    printf("请输入第%d个学生学号，姓名，语文，英语，数学成绩：\n",count+1);
    scanf("%d%s%d%d%d",s.num,&s.name,&s.chinese,&s.english,&s.math);
    s.sum=s.chinese+s.english+s.math;
    s.average=s.sum/3.0;
    students[count]=s;
    count++;
}
/*查询*/
void search_student(struct student students[],int num)
{
    int i;
    for(i=0;i<count;i++)
    {  
        if(students[i].num==num)      
        {
            printf("学生信息如下:\n");
            printf ("学号   姓名   语文   英语    数学    总分    平均分\n");   
            printf("%-8d%-8s%-8d%-8d%-8d%-8d%-8f\n",students[i].num,students[i].name, students[i].chinese,students[i].english,students[i].math,students[i].sum,students[i].average);
            break;
        }        
        else
            printf("无此学生信息\n");
    }
}
/*排序*/
void row_student(struct student students[])
{
    int i,j,index;  
    struct student temp;
    for(i=0;i<count-1;i++)   
    {
        index=i;  
        for(j=i+1;j<count;j++)     
        {  
            if(students[j].sum>students[index].sum)   
            {
                index=j;  
                temp=students[index];  
                students[index]=students[i];
                students[i]=temp;
            }
        }
    }
    printf("成绩排序如下：\n");  
    printf ("学号   姓名   语文   英语    数学    总分    平均分\n");
    for(i=0;i<count;i++)      
        printf("%-8d%-8s%-8d%-8d%-8d%-8d%-8f\n",students[i].num,students[i].name, students[i].chinese,students[i].english,students[i].math,students[i].sum,students[i].average);
}
/*删除*/
void delete_student(struct student students[],int num)
{
    int i;  
    for(i=0;i<count;i++)     
    {
        if(students[i].num==num)
            printf("删除成功\n");
        do        
        {
            students[i]=students[i+1];
            i++;
        }
        while(i<count-1);
    }
}
/*修改*/
void modify_student(struct student students[],int num)
{
    int i;  
    for(i=0;i<count;i++)  
    {  
        if(students[i].num==num)      
        {
            printf("你要修改的学生信息为:\n");
            printf ("学号   姓名   语文   英语    数学    总分    平均分\n");
            printf("%-8d%-8s%-8d%-8d%-8d%-8d%-8f\n",students[i].num,students[i].name, students[i].chinese,students[i].english,students[i].math,students[i].sum,students[i].average);
            printf("-- 请输入新值--\n");
            printf("请输入学号:");
            scanf("%s",&students[i].num);
            getchar();
            printf("请输入姓名:");
            scanf("%s",&students[i].name);
            getchar();
            printf("请输入语文成绩:");
            scanf("%f",&students[i].chinese);
            getchar();
            printf("请输入数学成绩:");
            scanf("%f",&students[i].math);
            getchar();
            printf("请输入英语成绩:");
            scanf("%f",&students[i].english);
            getchar();
            students[i].sum=students[i].chinese+students[i].math+students[i].english;
            students[i].average=students[i].sum/3.0;
        }
        else
        {
            printf("学生不存在!\n");
        }
        printf("是否继续?(y/n)");
        if (getchar()=='n')
        {
            break;
        }
    }
}

非常非常感谢，不过还有些小bug，比如说多条记录删除一条，会重复显示上一条，我自己再调一调试试。