学点 C 语言(24): 数据类型 结构(struct)

1. 结构就是多个变量的集合:

---

#include <stdio.h>

int main(void)
{
    struct Rec {
        int x;
        int y;
    };

    struct Rec r1;

    r1.x = 111;
    r1.y = 222;

    printf("%d, %d", r1.x, r1.y);
    
    getchar();
    return 0;
}

2. 定义时同时声明变量:

---

#include <stdio.h>

int main(void)
{
    struct Rec {
        int x,y;
    } r1,r2;

    r1.x = 111;
    r1.y = 222;

    r2.x = 333;
    r2.y = 444;

    printf("%d, %d\n", r1.x, r1.y);
    printf("%d, %d\n", r2.x, r2.y);
    
    getchar();
    return 0;
}

3. 定义时同时声明变量并赋值:

---

#include <stdio.h>

int main(void)
{
    struct Rec {
        int x,y;
    } r1 = {777,888};

    printf("%d, %d\n", r1.x, r1.y);
    
    getchar();
    return 0;
}

#include <stdio.h>

int main(void)
{
    struct Rec {
        char  name[12];
        short age;
    } r1 = {"ZhangSan", 12};

    printf("%s, %u", r1.name, r1.age);
    
    getchar();
    return 0;
}

4. 声明变量是赋初值:

---

#include <stdio.h>

int main(void)
{
    struct Rec {
        char  name[12];
        short age;
    };

    struct Rec r1 = {"ZhangSan", 12};

    printf("%s, %u", r1.name, r1.age);
    
    getchar();
    return 0;
}

5. 声明后给字符串赋值有点麻烦:

---

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

int main(void)
{
    struct Rec {
        char  name[12];
        short age;
    };

    struct Rec r1;

    strcpy(r1.name, "ZhangSan");
    r1.age  = 18;

    printf("%s, %u", r1.name, r1.age);
    
    getchar();
    return 0;
}

6. 如果在定义时直接声明变量, 可省略结构名:

---

#include <stdio.h>

int main(void)
{
    struct {
        char  name[12];
        short age;
    } r1 = {"ZhangSan", 12};

    printf("%s, %u", r1.name, r1.age);
    
    getchar();
    return 0;
}

7. 通过 scanf 赋值:

---

#include <stdio.h>

int main(void)
{
    struct Rec {
        char  name[12];
        short age;
    } r1;

    printf("name: ");
    scanf("%s", r1.name);

    printf("age: ");
    scanf("%d", &r1.age);

    printf("Name: %s; Age: %d", r1.name, r1.age);
    
    getchar(); getchar();
    return 0;
}