C++核心编程 14（四）赋值运算符重载

对于普通的数据类型函数，编译器知道该如何运算，但是对于自定义数据类型，编译器无法进行赋值，于是我们可以用到重载。

首先，系统会默认给一个类 创建至少三个函数 默认构造、析构、拷贝构造（简单值拷贝）。

若存在堆区代码，系统提供的值拷贝内存被重复释放会报错。所以需要用到深拷贝来解决这个问题。

class Person
{
public:
	Person(char* name, int age)
	{
		this->m_Name = new char[strlen(name) + 1];
		strcpy(this->m_Name, name);
		this->m_Age = age;
	}
	Person&operator=(const Person& p)
	{
		//先判断原来的堆区是否有数据 如果有先释放
		if (this->m_Name != NULL)
		{
			delete[]this->m_Name;
			this->m_Name = NULL;
		}
		this->m_Name = new char[strlen(p.m_Name) + 1];
		strcpy(this->m_Name, p.m_Name);
		this->m_Age = p.m_Age;

		return *this;
	}
	~Person()
	{
		if(this->m_Name!=NULL)
		{
			delete[]this->m_Name ;
			this->m_Name = NULL;

		}
	}
	char* m_Name;
	int m_Age;
};

void test01()
{
	Person p1("Tom", 18);

	Person p2("Jerry", 19);
	p1 = p2;
	cout << "p1的姓名:" << p1.m_Name << "年龄：" << p1.m_Age << endl;
	cout << "p2的姓名:" << p2.m_Name << "年龄：" << p2.m_Age << endl;

	Person p3("", 0);
	p3 = p1 = p2;
	cout << "p3的姓名:" << p3.m_Name << "年龄：" << p3.m_Age << endl;
}