C++基础知识 - 子类的析构函数

子类的析构函数

【注意】

• 为了防止内存泄露，最好是在基类析构函数上添加virtual关键字，使基类析构函数为虚函数
• 目的在于，当使用delete释放基类指针时，会实现动态的析构：
• 如果基类指针指向的是基类对象，那么只调用基类的析构函数
• 如果基类指针指向的是子类对象，那么先调用子类的析构函数，再调用父类的析构函数

#include <iostream>
#include <Windows.h>
using namespace std;

class Father {
public:
	Father(const char* name = "无名") {
		cout << "调用Father构造函数" << endl;
		this->name = new char[strlen(name) + 1];
		strcpy_s(this->name, strlen(name) + 1, name);
	}

	virtual ~Father() {
		if (name) {
			cout << "调用Father析构函数" << endl;
			delete[] name;
			name = NULL;
		}
	}
private:
	char* name;
};

class Son : public Father {
public:
	Son(const char* game = "篮球", const char* name = "无名") :Father(name) {
		cout << "调用Son构造函数" << endl;
		this->game = new char[strlen(game) + 1];
		strcpy_s(this->game, strlen(game) + 1, game);
	}

	~Son(){
		if (game) {
			cout << "调用Son析构函数" << endl;
			delete[] game;
			game = NULL;
		}
	}
private:
	char* game;
};

int main(void) {
	cout << "-------case1--------" << endl;
	Father *father = new Father();
	delete father;

	cout << "-------case2--------" << endl;
	Son* son = new Son();
	delete son;

	cout << "-------case3--------" << endl;
	father = new Son();
	delete father;
	
	system("pause");
	return 0;
}