day04_类

类

• C++中可以使用struct、class来定义一个类

• struct和class的区别

  • struct的默认成员权限是public
  • class的默认成员权限是private

  struct Person {
  	int m_id;
  	int m_age;
  	int m_height;
  
  	void display() {
  		cout << "m_id = " << this->m_id << endl;
  		cout << "m_age = " << this->m_age << endl;
  		cout << "m_height = " << this->m_height << endl;
  	}
  };
  
  struct Person {
  	int m_id;
  	int m_age;
  	int m_height;
  
  	void display() {
  		// this指向Person对象的指针
  		// this里面存储的就是Person对象的地址值
  		this->m_id = 5;
  		this->m_age = 6;
  		this->m_height = 7;
  
  		/*cout << "m_id = " << this->m_id << endl;
  		cout << "m_age = " << this->m_age << endl;
  		cout << "m_height = " << this->m_height << endl;*/
  	}
  };
  
  int main() {
  	Person person;
  	person.m_id = 10;
  	person.m_age = 20;
  	person.m_height = 30;
  
  	Person *pPerson = (Person *)&person.m_age;
  	pPerson->m_id = 40;
  	pPerson->m_age = 50;
  
  	person.display();
  
  	getchar();
  	return 0;
  }
  
  

C++****编程规范

• 全局变量:g_
• 成员变量:m_
• 静态变量:s_
• 常量:c_
• 使用驼峰标识

封装

成员变量私有化，提供公共的getter和setter给外界去访问成员变量

struct Person {
private:
	int m_age;

public:
	void setAge(int age) {
		// 过滤
		if (age < 0) return;

		this->m_age = age;
	}

	int getAge() {
		return this->m_age;
	}
};

int main() {
	Person person;
	person.setAge(-20);

	cout << person.getAge() << endl;

	getchar();
	return 0;
}