基本实现原理

/* 通过结构体+函数指针模拟类 */
typedef struct {// 成员变量int x;  // 成员方法（函数指针）                  void (*print)(void* self);  
} MyClass;/* 成员函数实现 */
void my_print(void* self) {MyClass* obj = (MyClass*)self;printf("Value: %d\n", obj->x);
}/* 构造函数 */
MyClass* MyClass_create(int x) {MyClass* obj = malloc(sizeof(MyClass));obj->x = x;obj->print = my_print;  // 方法绑定return obj;
}

🔀 三种核心特性实现

1. 封装

// 头文件（.h）中只声明结构体指针
typedef struct HiddenClass HiddenClass;// 源文件（.c）中定义真实结构体
struct HiddenClass {int private_data;void (*public_method)(HiddenClass*);
};

2. 继承

/* 基类 */
typedef struct {int base_val;void (*base_method)();
} Base;/* 派生类 */
typedef struct {Base super;  // 包含基类实现继承int derived_val;
} Derived;

3. 多态

typedef struct {void (*speak)();
} Animal;void dog_speak() { printf("汪汪汪\n"); }
void cat_speak() { printf("喵喵喵\n"); }Animal dog = { .speak = dog_speak };
Animal cat = { .speak = cat_speak };

🧩 完整示例：图形系统

/* 基类：Shape */
typedef struct Shape Shape;
struct Shape {void (*draw)(Shape*);
};/* 派生类：Circle */
typedef struct {Shape parent;  // 继承int radius;
} Circle;void circle_draw(Shape* self) {Circle* c = (Circle*)self;printf("绘制半径%d的圆\n", c->radius);
}Circle* create_circle(int r) {Circle* c = malloc(sizeof(Circle));c->parent.draw = circle_draw;c->radius = r;return c;
}

备注

个人水平有限，有问题随时交流~