结构体初始化的几种方法



1.先定义再初始化

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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

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// 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

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// 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

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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

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

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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

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

obj_t obj_9;

7.成员函数

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void fn() {
    ;
}

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

obj_t obj_10 = {.function = fn};