c语言学习之基础知识点介绍（十七）：写入读取结构体、数组、结构体数组

一、结构体的写入和读取

   //写入结构体
    FILE *fp = fopen("/Users/ios/Desktop/1.data", "w");
    if (fp) {

//        int num = 20;
//        fwrite(&num, sizeof(num), 1, fp);//写入int

        Person p = {"苍空",16}; //int num = 20;
        fwrite(&p, sizeof(p), 1, fp);
        printf("写完了
");
        fclose(fp);
    }
    
    //读取结构体
    FILE *fp = fopen("/Users/ios/Desktop/1.data", "r");
    if(fp){
        Person p;
        fread(&p, sizeof(p), 1, fp);
        printf("姓名：%s  年龄：%d
",p.name,p.age);
        fclose(fp);
    }

二、数组的写入和读取

//写入数组
    FILE *fp = fopen("/Users/ios/Desktop/1.xxxx", "w");
    
    if(fp){
        float fs[] = {10.1f,10.2f,10.3f,10.4f,10.5f};//数组名本身就是地址
        fwrite(&fs, sizeof(float), 5, fp);//第二个参数：每个元素的大小，第三个：一共多少块，多少块以数组长度为结果
        printf("haha
");
        fclose(fp);
    }
    
    //读取数组
    FILE *fp = fopen("/Users/ios/Desktop/1.xxxx", "r");
    if(fp){
        float fs[5];
        fread(&fs, sizeof(float), 5, fp);
        for (int i =0; i<5; i++) {
            printf("%.1f
",fs[i]);
        }
        fclose(fp);
    }

三、结构体数组的写入和读取

  //结构体数组的写入
    
    FILE *fp = fopen("/Users/ios/Desktop/xxx.1", "w");
    if (fp) {
        Person ps[4] = { {"刘",16},{"张",17},{"郭",18},{"花",14} };
        fwrite(ps, sizeof(Person), 4, fp);
        printf("第1个天王最帅
");
        fclose(fp);
    }
    
    
    //结构体数组的读取
    FILE *fp = fopen("/Users/ios/Desktop/xxx.1", "r");
    if (fp) {
        //读取
        Person ps[4];
        fread(ps, sizeof(Person), 4, fp);
        for (int i = 0; i<4; i++) {
            printf("姓名：%s  年龄：%d
",ps[i].name,ps[i].age);
        }
        fclose(fp);
    }