运算符重载(个人学习笔记黑马学习)

1、加号运算符重载

#include <iostream>
using namespace std;
#include <string>

//加号运算符重载
class Person {
public:

	//1、成员函数重载+号
	//Person operator+(Person& p) {
	//	Person temp;
	//	temp.m_A = this->m_A + p.m_A;
	//	temp.m_B = this->m_B + p.m_B;
	//	return temp;
	//}

	int m_A;
	int m_B;
};


//2、全局函数重载+号 
Person operator+(Person &p1,Person &p2) {
	Person temp;
	temp.m_A= p1.m_A + p2.m_A;
	temp.m_B = p1.m_B + p2.m_B;
	return temp;
}

//函数重载的版本
Person operator+(Person& p1, int num) {
	Person temp;
	temp.m_A = p1.m_A + num;
	temp.m_B = p1.m_B + num;
	return temp;
}

void test01() {
	Person p1;
	p1.m_A = 10;
	p1.m_B = 10;

	Person p2;
	p2.m_A = 10;
	p2.m_B = 10;

	//成员函数重载本质调用
	//Person p3 = p1.operator+(p2);

	//全局函数重载本质调用
	//Person p3 = operator+(p1, p2);

	//运算符重载 也可以发生函数重载
	Person p4 = p1 + 100;// Person + int
	cout << "p4.m_A = " << p4.m_A << endl;
	cout << "p4.m_B = " << p4.m_B << endl;

	Person p3 = p1 + p2;

	cout << "p3.m_A = " << p3.m_A << endl;
	cout << "p3.m_B = " << p3.m_B << endl;
}





int main() {

	test01();

	system("pause");
	return 0;
}

---

2、左移运算符重载

#include <iostream>
using namespace std;
#include <string>

//左移运算符

class Person {
	friend ostream& operator<<(ostream& cout, Person& p);
//public:

public:
	Person(int a, int b) {
		m_A = a;
		m_B = b;
	}
private:
	//利用成员函数重载 左移运算符 p,operator<<(cout) 简化版本p<<cout
	//不会利用成员函数重载<<运算符 因为无法实现 cout在左侧
	/*void operator<<(cout) {

	}*/

	int m_A;
	int m_B;

};
//只能利用全局函数重载左移运算符
ostream& operator<<(ostream& cout, Person& p) {//本质：operator<<(cout,p)  简化cout<<p
	cout << "m_A = " << p.m_A << " m_B = " << p.m_B ;
	return cout;

}

void test01() {
	/*Person p;
	p.m_A = 10;
	p.m_B = 10;*/

	Person p(10,10);

	cout << p << endl;;
}

int main() {

	test01();

	system("pause");
	return 0;
}

---

3、递增运算符重载

#include <iostream>
using namespace std;
#include <string>

//递增运算符重载

//自定义整型
class MyInteger {

	friend ostream& operator<<(ostream& cout, MyInteger myint);

public:
	MyInteger() {
		m_Num = 0;
	}

	//重载前置++运算符  返回引用为了一直对一个数据进行递增操作
	MyInteger& operator++() {
		//先进行++运算  在将自身做返回
		m_Num++;
		return *this;
	}

	//重载后置++运算符
	//void operator++(int) int代表占位参数，可以用于区分前置和后置

	MyInteger operator++(int) {
		//先 记录当前结果
		MyInteger temp = *this;
		//后递增
		m_Num++;
		//最后将记录结果做返回
		return temp;
	}

private:
	int m_Num;
};

//重载<<运算符
ostream& operator<<(ostream& cout, MyInteger myint) {
	cout << myint.m_Num;
	return cout;
}

void test01() {
	MyInteger myint;
	//cout << ++myint << endl;
	cout << ++(++myint) << endl;
	cout << myint << endl;
}

void test02() {
	MyInteger myint;
	cout << myint++ << endl;
	cout << myint << endl;
}

int main() {

	//test01();
	test02();

	system("pause");
	return 0;
}

---

4、赋值运算符重载

#include <iostream>
using namespace std;
#include <string>

//赋值运算符重载
class Person {
public:

	Person(int age) {
		m_Age=new int(age);
	}

	~Person() {
		if (m_Age != NULL) {
			delete m_Age;
			m_Age = NULL;
		}
	}

	//重载 赋值运算符
	Person& operator=(Person& p) {
		//编译器提供浅拷贝
		//m_Age = p.m_Age;
		
		//应该先判断是否有属性在堆区，如果有先释放干净，融合再深拷贝
		if (m_Age != NULL) {
			delete m_Age;
			m_Age = NULL;
		}

		//深拷贝
		m_Age = new int(*p.m_Age);

		return *this;
	}

	int* m_Age;
};

void test01() {
	Person p1(18);
	Person p2(20);
	Person p3(30);


	p3 = p2 = p1;//赋值操作


	cout << "p1的年龄为：" << *p1.m_Age << endl;
	cout << "p2的年龄为：" << *p2.m_Age << endl;
	cout << "p3的年龄为：" << *p3.m_Age << endl;

}

int main() {

	test01();

	system("pause");
	return 0;
}

---

5、关系运算符重载

#include <iostream>
using namespace std;
#include <string>

//重载关系运算符

class Person {
public:
	Person(string name, int age) {
		m_Name = name;
		m_Age = age;
	}

	//重载关系运算符==
	bool operator== (Person& p) {
		if (this->m_Name == p.m_Name && this->m_Age == p.m_Age) {
			return true;
		}
		return false;
	}

	//重载关系运算符!=
	bool operator!= (Person& p) {
		if (this->m_Name == p.m_Name && this->m_Age == p.m_Age) {
			return false;
		}
		return true;
	}

	string m_Name;
	int m_Age;
};

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

	Person p2("Tom", 18);

	if (p1 == p2) {
		cout << "p1和p2是相等的" << endl;
	}
	else {
		cout << "p1和p2是不相等的" << endl;

	}


	if (p1 != p2) {
		cout << "p1和p2是不相等的" << endl;
	}
	else {
		cout << "p1和p2是相等的" << endl;

	}

}


int main() {

	test01();

	system("pause");
	return 0;
}

---

6、函数调用运算符重载

#include <iostream>
using namespace std;
#include <string>

//函数调用运算符重载

//打印输出类
class MyPrint {
public:

	//重载函数调用运算符
	void operator()(string test){
		cout << test << endl;
	}
};

void test01() {
	MyPrint myPrint;

	myPrint("hello world");//由于使用起来非常类似于函数调用 因此称为仿函数

}

//仿函数非常灵活，没有固定的写法
//加法类

class MyAdd {
public:
	int operator()(int num1, int num2) {
		return num1 + num2;
	}
};

void test02() {
	MyAdd myadd;
	int ret=myadd(100, 100);
	cout << "ret = " << ret << endl;

	//匿名函数对象
	cout << MyAdd()(100, 100) << endl;
}

int main() {

	//test01();
	test02();


	system("pause");
	return 0;
}