结构体

结构体可以用于存储不同类型的数据，还可以保持成员（Menber）信息的独立

1. 结构体的声明和结构体变量的定义

#include <stdio.h>                          //标准输入输出头文件
#include <string.h>                         //字符串处理函数的头文件

int main() {                               
	struct Person {     
	char  name[20];
	char  address[20];
	 } A;                                //结构体模板声明：struct 结构体类型名  {成员变量列表......} 结构体变量名;  其中Person是结构体类型名，name和address是成员变量，A是结构体变量名

	struct Person B;                     //声明好结构体模板后，就可以通过  struct  结构体类型名 结构体变量名 来声明结构体变量；
	strcpy_s(A.name, "Li Ming");       
	printf("%s", A.name);
        strcpy_s(B.name, "Li Hua");       
	printf("%s", B.name);
	return 0;
}

2.结构体数组

#include <stdio.h>
#include <string.h>
#define MAXTITL 30
#define MAXAUTH 30
#define MAXBKS 100

struct book {                                       //声明结构体模板
	char title[MAXTITL];
	char author[MAXAUTH];
	float value;
}; 

struct book library[MAXBKS];           //声明结构体数组，其中library[0]，library[1]，library[2]...为相互独立的结构体变量

int main() {
	strcpy_s(library[0].title, "A tale of two cities");  // library[0].title 用于调用结构体变量library[0]的成员变量title
	strcpy_s(library[0].author, "Dickens");             
	library[0].value = 30;
	printf("%s\n%s\n%f\n", library[0].title, library[0].author, library[0].value);
}

3.嵌套结构

#include <stdio.h>
#include <string.h>
#include <math.h>
struct point {
	float x;
	float y;
};

struct rect {
	struct point pt1;
	struct point pt2;
};

struct rect A;

int main() {
	printf("请输入长方形的左下顶点坐标\n");
	scanf_s("%f,%f", &A.pt1.x, &A.pt1.y);
	
	printf("请输入长方形的右上顶点坐标\n");
	scanf_s("%f,%f", &A.pt2.x, &A.pt2.y);
	
	printf("长方形的面积为：%f\n",(A.pt2.x- A.pt1.x)*(A.pt2.y- A.pt1.y));
}

4.指向结构的指针

#include <stdio.h>
#include <string.h>
#define LEN 20

struct name {
	char first[LEN];
	char last[LEN];
};

struct guy {
	struct name handle;
	char favfood[LEN];
	char job[LEN];
	float income;
};

int main(void)
{
	struct guy fellow[2] = {
		{{"Ewen","Villard"},"grilled salmon","personality coach",68112.00},
		{{"Rodney","Swillbelly"}, "tripe", "tabloid editor", 432400.00}
	};

	struct guy* him;

	printf("address #1:%p #2: %p\n", &fellow[0], &fellow[1]);
	him = fellow;
	printf("address #1:%p #2: %p\n", him, him+1);
	printf("him->handle.first %s,him->handle.last is %s\n", him->handle.first, him->handle.last);
	printf("him->income is $%.2f,(*him)->income is $%.2f\n", him->income,(*him).income);
};

5.结构体作为函数参数

#include <stdio.h>
#include <string.h>

/*声明结构体模板*/
struct Books
{
	char  title[50];
	char  author[50];
	char  subject[100];
	int   book_id;
};

/* 函数声明 */
void printBook(struct Books book);

int main()
{
	struct Books Book1;        /* 声明 Book1，类型为 Books */
	struct Books Book2;        /* 声明 Book2，类型为 Books */

	/* Book1 详述 */
	strcpy_s(Book1.title, "C Programming");
	strcpy_s(Book1.author, "Nuha Ali");
	strcpy_s(Book1.subject, "C Programming Tutorial");
	Book1.book_id = 6495407;

	/* Book2 详述 */
	strcpy_s(Book2.title, "Telecom Billing");
	strcpy_s(Book2.author, "Zara Ali");
	strcpy_s(Book2.subject, "Telecom Billing Tutorial");
	Book2.book_id = 6495700;

	/* 输出 Book1 信息 */
	printBook(Book1);

	/* 输出 Book2 信息 */
	printBook(Book2);

	return 0;
}
/*定义函数*/
void printBook(struct Books book)
{
	printf("Book title : %s\n", book.title);
	printf("Book author : %s\n", book.author);
	printf("Book subject : %s\n", book.subject);
	printf("Book book_id : %d\n", book.book_id);
}