C++之虚析构

zy010101

发布于 2020-04-08 16:49:35

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代码可运行

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代码可运行

在继承的时候，父类的指针（或引用）可以指向（引用）子类的对象。如果子类有自己的指针属性，那么就需要将父类的析构函数声明为虚析构函数，否则通过父类指针（或者引用）无法调用子类的析构函数。

下面这段代码演示了这种情形

#define  _CRT_SECURE_NO_WARNINGS

#include<iostream>

using std::cout;
using std::endl;

class Parent
{
public:
	int a, b;
	char* name;
	Parent(int a = 0, int b = 0,char *name = nullptr)	//构造函数
	{
		this->a = a;
		this->b = b;
		this->name = (char*)malloc(strlen(name) + 1);
		strcpy(this->name, name);
	}
	Parent(const Parent& p)				//拷贝构造函数
	{
		this->a = p.a;
		this->b = p.b;
		this->name = (char*)malloc(strlen(p.name) + 1);
		strcpy(this->name, name);
	}
	~Parent()							//析构函数
	{
		if (nullptr != this->name)
		{
			free(this->name);
			this->name = nullptr;
		}
		cout << "基类析构函数" << endl;

	}
};

class Son : public Parent
{
public:
	Son(int a = 0, int b = 0, char* name = nullptr,char* last_name = nullptr):Parent(a,b,name)
	{
		this->last_name = (char*)malloc(strlen(last_name) + 1);
		strcpy(this->last_name, last_name);
	}
	~Son()
	{
		if (nullptr != this->last_name)
		{
			free(this->last_name);
			this->last_name = nullptr;
		}
		cout << "派生类析构函数" << endl;
	}

private:
	char* last_name;
};



int main()
{
	char name[10] = "White";
	char last_name[10] = "Smith";
	Parent *s = new Son(3, 4, name, last_name);

	delete s;

	return 0;
}