4.5运算符重载
运算符重载概念:对已有的运算符重新定义,赋予其另一种功能,以适应不同的数据类型
4.5.1加号运算符重载
作用:实现两个自定义的数据类型相加
cpp
#include<iostream>
using namespace std;
//加号运算符重载
//1.成员函数重载+号
//2.全局函数重载+号
class Person
{
public:
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;
Person p3 = p1 + p2;
//本质:Person p3=operator+(p1,p2)
cout << "p3.m_A= " << p3.m_A << endl;
cout << "p3.m_B= " << p3.m_B << endl;
//运算符重载 也可以发生函数重载
Person p4 = p1 + 100;
cout << "p4.m_A= " << p4.m_A << endl;
cout << "p4.m_B= " << p4.m_B << endl;
}
int main()
{
test01();
return 0;
}
cpp
#include<iostream>
using namespace std;
//加号运算符重载
//1.成员函数重载+号
//2.全局函数重载+号
class Person
{
public:
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;
Person p3 = p1 + p2;
//本质:Person p3=operator+(p1,p2)
cout << "p3.m_A= " << p3.m_A << endl;
cout << "p3.m_B= " << p3.m_B << endl;
//运算符重载 也可以发生函数重载
Person p4 = p1 + 100;
cout << "p4.m_A= " << p4.m_A << endl;
cout << "p4.m_B= " << p4.m_B << endl;
}
int main()
{
test01();
return 0;
}
4.5.2左移运算符重载
cpp
#include<iostream>
using namespace std;
class Person
{
public:
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 p1,p2;
p1.m_A = 10;
p1.m_B = 10;
p2.m_A = 20;
p2.m_B = 20;
cout << p1 << p2;
}
int main()
{
test01();
return 0;
}
cpp
#include<iostream>
using namespace std;
class Person
{
public:
Person(int a, int b)
{
m_A = a;
m_B = b;
}
friend ostream& operator<<(ostream& cout, Person& p);
private:
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 p1(10, 10);
Person p2(20, 20);
cout << p1 << p2;
}
int main()
{
test01();
return 0;
}
4.5.3递增运算符重载
cpp
#include<iostream>
using namespace std;
class Myintrgger
{
friend ostream& operator<<(ostream& cout, Myintrgger myint);
public:
Myintrgger()
{
m_Num = 0;
}
//重载前置++运算符
//返回引用是为了一直对一个数据相加
Myintrgger& operator++()
{
m_Num++;//先做一个++运算,再返回
return *this;
}
//重载后置++运算符
//后置递增返回的是值
Myintrgger operator++(int)//int代表占位参数,区分前置后置
{
//先记录当时的结果
Myintrgger temp = *this;
//后递增
m_Num++;
//最后将记录结果返回
return temp;
}
private:
int m_Num;
};
//重载左移运算发
ostream& operator<<(ostream& cout, Myintrgger myint)
{
cout << myint.m_Num << endl;
return cout;
}
void test01()
{
Myintrgger myint;
cout << ++myint;
cout << myint;
}
void test02()
{
Myintrgger myint;
cout << myint++;
cout << myint;
}
int main()
{
test01();
test02();
return 0;
}
重载右移运算符
cpp
#include<iostream>
using namespace std;
class Myintter
{
friend ostream& operator<<(ostream& cout, Myintter myint);
public:
Myintter()
{
m_Num = 2;
}
//重载前置--
Myintter& operator--()
{
m_Num--;
return *this;
}
Myintter operator--(int)
{
Myintter temp = *this;
m_Num--;
return temp;
}
private:
int m_Num;
};
ostream& operator<<(ostream& cout, Myintter myint)
{
cout << myint.m_Num << endl;
return cout;
}
void test01()
{
Myintter myint;
cout << --myint << myint;
}
void test02()
{
Myintter myint;
cout << myint--<<myint;
}
int main()
{
test01();
test02();
return 0;
}
赋值运算符重载
cpp
#include<iostream>
using namespace std;
class Person
{
public:
Person(int age)
{
m_Age = new int(age);
}
~Person()
{
if (m_Age != (NULL))
{
delete m_Age;
m_Age = NULL;
}
}
int* m_Age;
};
void test01()
{
Person p1(18);
Person p2(20);
p2 = p1;
cout << "p1的年龄为:" << *p1.m_Age << endl;
cout << "p2的年龄为:" << *p2.m_Age << endl;
}
int main()
{
test01();
}
上述代码为浅拷贝,delete重复释放堆区内存,代码出错
解决方案,深拷贝代替浅拷贝
cpp
#include<iostream>
using namespace std;
class Person
{
public:
Person(int age)
{
m_Age = new int(age);
}
~Person()
{
if (m_Age != (NULL))
{
delete m_Age;
m_Age = NULL;
}
}
Person& operator=(Person &p)
{
//编译器提供的浅拷贝
//m_Age=p.m_Age;
//应先判断是否有属性在堆区,先把p2原来的内存释放干净,然后在深拷贝
if (m_Age != NULL)
{
delete m_Age;
m_Age = NULL;
}
//深拷贝
m_Age = new int(*p.m_Age);//自身指向新的空间
return * this;
}
int* m_Age;
};
void test01()
{
Person p1(18);
Person p2(20);
Person p3(30);
p2 = p1;
p3 = p2 = p1;
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();
return 0;#include<iostream>
using namespace std;
class Person
{
public:
Person(string name, int age)
{
m_name = name;
m_Age = age;
}
//重载==
bool operator==(Person& p)
{
if (this->m_name == p.m_name && this->m_Age == p.m_Age)
{
return true;
}
return false;
}
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("zhangsan", 18);
Person p2("zhangsan", 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();
return 0;
}
}
4.5.5关系运算符重载
cpp
#include<iostream>
using namespace std;
class Person
{
public:
Person(string name, int age)
{
m_name = name;
m_Age = age;
}
//重载==
bool operator==(Person& p)
{
if (this->m_name == p.m_name && this->m_Age == p.m_Age)
{
return true;
}
return false;
}
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("zhangsan", 18);
Person p2("zhangsan", 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();
return 0;
}
4.5.6函数调用操作符重载
cpp
#include<iostream>
#include<string>
using namespace std;
class Myprint
{
public:
//仿函数非常灵活
void operator()(string text)
{
cout << text << endl;
}
};
void Myprint02(string test)
{
cout << test << endl;
}
void test01()
{
Myprint myprint;
myprint("hello word");//重载
Myprint02("hello word");//函数调用
}
class Myadd//加法类
{
public:
int operator()(int num1, int num2)
{
return num2 + num2;
}
};
void test02()
{
Myadd myadd;
int ret = myadd(100, 200);
cout << "ret= " << ret<< endl;
cout << Myadd()(100, 200) << endl;//匿名对象,程序执行完成,立即被释放
}
int main()
{
test01();
test02();
return 0;
}