C语言中文件的打开问题

int main()
{
    struct StudentType student[1000]={
            {1001,"张大仙","男",29,20},
            {1002,"大黑龙","龙",158,98},
            {1003,"小帅哥","男",65,66},
            {1004,"小美女","女",18,55}
        };
    StudentType *pstudent;
    pstudent=student;
    int size=sizeof(struct StudentType);
    FILE *fp=fopen("C:\\Users\HR\Desktop\555.txt","wb+");
        if( (fp=fopen("C:\\Users\HR\Desktop\555.txt","wb+"))==NULL)
        {  //以二进制方式打开
            puts("Fail to open file!");
            return(0);
        }
    fwrite(pstudent,size,5,fp);
    rewind(fp);
    fread(pstudent,size,5,fp);
        fclose(fp);

wb 不是二进制写入吗？你这写进去的是二进制？

这个目录必须是已经建立好的，C:\Users\HR\Desktop，修改如下，供参考：

#include <stdio.h>
struct StudentType {
    int  num;
    char name[16];
    char sex[4];
    int  age;
    int  len;
};
int main()
{
    struct StudentType student[1000] = {
            {1001,"张大仙","男",29,20},
            {1002,"大黑龙","龙",158,98},
            {1003,"小帅哥","男",65,66},
            {1004,"小美女","女",18,55}
    };
    struct StudentType* pstudent,stu[4];  //修改
    pstudent = student;
    int size = sizeof(struct StudentType),i; //修改
    FILE* fp = fopen("C:\\Users\\HR\\Desktop\\555.txt", "wb+");//"C:\\Users\HR\Desktop\555.txt
    if (fp == NULL)//if ((fp = fopen("C:\\Users\HR\Desktop\555.txt", "wb+")) == NULL)
    {  //以二进制方式打开
        puts("Fail to open file!");
        return(0);
    }
    fwrite(pstudent, size, 4, fp);
    rewind(fp);
    fread(stu, size, 4, fp);
    pstudent = stu;  i = 0;
    while(i<4){
        printf("%d %s %s %d %d\n", pstudent->num, pstudent->name, pstudent->sex, pstudent->age, pstudent->len);
        pstudent++; i++;
    }
    fclose(fp);
}