结构体初始化的几种方法

1.先定义再初始化

struct obj_t {
          
   
    const char *name;
    int val;
};

obj_t obj;
obj.name = "ABC";
obj.val = 0;

2.定义的时候初始化

// 写法1 按照顺序赋值
struct {
          
   
    const char *name;
    int val;
} obj_2 = {
          
   "ABD", 0};

// 写法2 单独对成员赋值
struct {
          
   
    const char *name;
    int val;
} obj_3 = {
          
   .name = "ABD", .val = 0};

// 写法3
struct obj_t {
          
   
    const char *name;
    int val;
};
obj_t obj_1 = {
          
   .name = "name", .val = 0};

3.结构体嵌套

// 写法1
struct {
          
   
    const char *name;
    int val;
    struct{
          
   
        int a;
    }obj;
} obj_4 = {
          
   "ABD", 0, 666};

// 写法2
struct {
          
   
    const char *name;
    int val;
    struct{
          
   
        int a;
    }obj;
} obj_5 = {
          
   .name = "ABD", .val = 0, {
          
   .a = 666}};

4.结构体数组

struct {
          
   
    const char *name;
    int val;
} obj_6[2] = {
          
   [0] = {
          
   "name 0", 0}, [1]= {
          
   "name 1", 1}};

5.结构体嵌套数组

struct {
          
   
    const char *name;
    int val;
    struct{
          
   
        int a;
    }obj;
} obj_7[2] = {
          
   [0] = {
          
   "name 0", 0, 0}, [1] = {
          
   "name 1"}};

struct obj_t {
          
   
    const char *name;
    int val;
    struct {
          
   
        int a;
    } obj;
};

obj_t obj_8[2] = {
          
   
        [0] = {
          
   "name 0", 0, 0},
        [1] = {
          
   "name 1", 0, 0}
};

6.使用类型别名

typedef struct {
          
   
    const char *name;
    int val;
} obj_t;

obj_t obj_9;

7.成员函数

void fn() {
          
   
    ;
}

typedef struct {
          
   
    const char *name;
    int val;
    void (*function)();
} obj_t;

obj_t obj_10 = {
          
   .function = fn};