linux下fwrite的代码与fread的代码

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
struct stu
{
    char name[10];
    int age;
};

int main()
{
    struct stu mystu[3];
    FILE * fp;
    extern int errno;
    char file[]="/home/txt1.txt";
    int i;

    strcpy(mystu[0].name,"Jim");
    mystu[0].age=22;
    strcpy(mystu[1].name,"Jam");
    mystu[1].age=43;
    strcpy(mystu[2].name,"Lily");
    mystu[2].age=18;

    fp=fopen(file,"a+");
    if(fp==NULL)
    {
        printf("can't open file %s.\n",file);
        printf("errno:%d\n",errno);
        printf("ERR :%s\n",strerror(errno));
    }
    else
    {
        printf("%s was opend .\n",file);

    }
    i=fwrite(mystu,sizeof(struct stu),3,fp);
    printf("%d items was written .\n",i);
    close(fp);
    return 0;

}

以上是fwrite的代码：

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
struct stu
{
    char name[10];
    int age;
}stu1[3];

int main()
{

    FILE * fp;
    extern int errno;
    char file[]="/home/txt1.txt";
    int i;

    fp=fopen(file,"a+");
    if(fp==NULL)
    {
        printf("can't open file %s.\n",file);
        printf("errno:%d\n",errno);
        printf("ERR :%s\n",strerror(errno));
    }
    else
    {
        printf("%s was opend .\n",file);

    }
    printf("%d\n",sizeof(struct stu));
    for(i=0; i<3; i++)
    {
        fread(&stu1,sizeof(struct stu),3,fp);
        printf("%s,%d\n",stu1[i].name,stu1[i].age);
    }



// printf("%d items was written .\n",i);
    fclose(fp);
    return 0;



}

以上是fread的代码：