结构体

struct 结构体类型名称｛
   成员类型  成员名称
｝;   //必须加分号

struct Person{
   int age;
   char sex;
   double height;
   double weight;
   char *name;
}

3.2 通过结构体类型定义结构变量

struct 结构类型名称 结构体变量名称;

struct Person person;

3.3 访问结构体成员

person.age = 10;
person.sex = ‘M‘;
person.weight=20.2;
person.height=1.2;
person.name="小明";
printf("age=%d,sex=%c,weight=%.2lf,height=%.2lf,name = %s\n",person.age,person.sex,person.weight,person.height,person.name);

p1 = p2;

void test(){
    struct Person{
        int age;
        double height;
    };
    struct Person p1;
}

void test1(){
    struct Person{
        int age;
        double height;
    }p1,p2={20,1.75};
    p1 = (struct Person){10,1.2};
}

truct Person{
        int age;
        double height;
    }p1,p2={20,1.75};

#include <stdio.h>
int main(){
    struct Date{
        int year;
        int month;
        int day;
    };
    struct Date date;
    
    printf("%p\n",&date);
    printf("%p\n",&date.year);
    
}

#include <stdio.h>
#pragma pack(3)
int main(){

结构类型类型 数组名称[元素个数];

//一般情况下，结构体类型一般定义在函数外部
struct Dog{
    char *name;
    int age;
};
int main(){
    //定义，结构体如果没有初始化，它里面都是垃圾值
    struct Dog dogs[5];
    //初始化
    dogs[0](struct Dog){"旺财",1};
    dogs[1].age=1;
    dogs[1].name="大黄";
    return 0;
}

struct Dog dogs[10] = {{"旺财",1},{"大黄",2},{"来福",3},{"小黑",4},{"小白",5}};

int len = sizeof(dogs)/sizeof(struct Dog);

指针所指数据类型 * 指针变量名称

struct Student{
    char *name;
    int no;
    double score;
};
int main(){
    struct Student stu = {"小黑",60,59};
    //定义结构体指针
    struct Student *sp1;
    //赋值
    sp1 = &stu;
    //定义的同时进行赋值
    struct Student *sp2 = &stu;
    return 0;
}

2 通过指针访问结构体成员

(*sp1).score = 60;

• 第二种方法（推荐）
  

sp2->name = "大白";
sp2->no = 59;

//定义一个日期的结构体
struct Date{
    int year;
    int month;
    int day;
};
//定义员工结构体，其中包括日期结构
struct Employee{
    int num;
    char *name;
    struct Date birthday;   //这就是结构体嵌套
};

struct Employee emp = {1,"八戒",{2015,9,8}};

struct Person{
    char *name;
    struct Person *son;  //这是可以的，可以嵌套自己类型的指针
};

九 结构体函数

//结构体作为函数参数
void printPerson(struct Person person){
    printf("name=%s,age=%d,height=%.2f\n",person.name,person.age,person.height);
}
int main(){
    struct Person p = {"小孩",1,0.2};
    printPerson(p);
}

//结构体作为函数参数
void printPerson(struct Person person){
    printf("name=%s,age=%d,height=%.2f\n",person.name,person.age,person.height);
}
void changePerson(struct Person person){
    person.age = 30;
}
int main(){
    struct Person p = {"晋三",1,0.2};
    printPerson(p);
    changePerson(p);
    printPerson(p);
}

//结构体作为函数参数
void printPerson(struct Person person){
    printf("name=%s,age=%d,height=%.2f\n",person.name,person.age,person.height);
}
void changePerson2(struct Person *person){
    person.age = 30;
}
int main(){
    struct Person p = {"晋三",1,0.2};
    printPerson(p);
    changePerson2(&p);
    printPerson(p);
}

//写一个函数遍历结构体数组
void printPersons(struct Person *persons,int len){
    for(int i=0;i<len;i++){
        printf("name=%s,age=%d,height=%.2f\n",persons[i].name,persons[i].age,persons[i].height);
    }
}
//更新
void changePersons(struct Person *persons,int len){
    //省略...
}
int main(){
    struct Person ps[3]={{"小泉",2,0.3},{"晋三",2,0.3}};
    int len = sizeof(ps)/sizeof(struct Person);
    printPersons(ps,len);
    changePersons(ps,len);
    printfPersons(ps,len);
}