物联网综合应用 第二次作业

Posted 2021-10-09 wangsitiao

1. pwd查看当前目录 在当前目录 mkdir zuoye02 新建目录

2. cd zuoye02 进入文件夹 

3.vim write.c

#include<stdio.h>
#include<fcntl.h>
#include<unistd.h>
struct stu {
    char name[20];
    int id;
    int age;
    char sex;
};

int main() {
    struct stu student[3] = {{"学生0", 1, 10, 'M'},
                             {"学生1", 2, 20, 'G'},
                             {"学生2", 3, 21, 'M'}};

    int i,j = 0, fd = open("./stu.dat", O_RDWR | O_CREAT, 0644), buf = 0;
    for (; i < 3; i++) {
        write(fd, &student[i], sizeof(student[i]));
    }

    for (; j < 3; j++) {
        lseek(fd, 24 + j * 32, SEEK_SET);
        read(fd, &buf, sizeof(buf));
        printf("学生%d的年龄为%d\\n", j, buf);
    }
    close(fd);
    return 0;
}

4. gcc -o write write.c

5. ./write 运行