C++类和对象-C++运算符重载-＞加号运算符重载、左移运算符重载、递增运算符重载、赋值运算符重载、关系运算符重载、函数调用运算符重载
#include
using namespace std;
//加号运算符重载
class Person {
public:
Person() {};
Person(int a, int b)
{
this->m_A = a;
this->m_B = b;
}
//1.成员函数实现 + 号运算符重载
Person operator+(const Person& p) {
Person temp;
temp.m_A = this->m_A + p.m_A;
temp.m_B = this->m_B + p.m_B;
return temp;
}
public:
int m_A;
int m_B;
};
//2.全局函数实现 + 号运算符重载
//Person operator+(const Person& p1, const Person& p2) {
// Person temp(0, 0);
// temp.m_A = p1.m_A + p2.m_A;
// temp.m_B = p1.m_B + p2.m_B;
// return temp;
//}
//运算符重载 可以发生函数重载
Person operator+(const Person& p2, int val)
{
Person temp;
temp.m_A = p2.m_A + val;
temp.m_B = p2.m_B + val;
return temp;
}
void test() {
Person p1(10, 10);
Person p2(20, 20);
//成员函数重载本质调用
Person p3 = p2 + p1; //相当于 p2.operaor+(p1)
cout << "mA:" << p3.m_A << " mB:" << p3.m_B << endl;
//全局函数重载本质调用
Person p4 = p1 + p2; //相当于 operator+(p1,p2)
cout << "mA:" << p4.m_A << " mB:" << p4.m_B << endl;
//运算符重载 也可以发生函数重载
Person p5 = p3 + 10; //相当于 operator+(p3,10)
cout << "mA:" << p5.m_A << " mB:" << p5.m_B << endl;
}
int main() {
test();
system("pause");
return 0;
}
总结1：对于内置的数据类型的表达式的的运算符是不可能改变的
总结2：不要滥用运算符重载
#include
using namespace std;
//左移运算符重载
class Person
{
friend ostream& operator<<(ostream& cout, Person& p);
public:
Person(int a, int b)
{
this->m_A = a;
this->m_B = b;
}
//利用成员函数重载 左移运算符
//成员函数 实现不了 p << cout 不是我们想要的效果
//void operator<<(Person& p){
//}
private:
int m_A;
int m_B;
};
//只能利用全局函数重载实现左移运算符
//ostream对象只能有一个
ostream& operator<<(ostream& cout, Person& p) //本质 operator<<(cout,p) 简化 cout<
cout << "a:" << p.m_A << " b:" << p.m_B;
return cout;
}
void test()
{
Person p1(10, 20);
cout << p1 << " hello world" << endl; //链式编程
}
int main()
{
test();
system("pause");
return 0;
}
总结：重载左移运算符配合友元可以实现输出自定义数据类型
#include
using namespace std;
//重载递增运算符
//自定义整型
class MyInteger
{
friend ostream& operator<<(ostream& out, 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++
m_Num++;
//再返回
return *this;
}
//重载后置++运算符
//int代表占位参数，可以用于区分前置和后置递增
MyInteger operator++(int)
{
//先 记录当前结果
MyInteger temp = *this; //记录当前本身的值，然后让本身的值加1，但是返回的是以前的值，达到先返回后++；
//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& out, MyInteger myint)
{
out << myint.m_Num;
return out;
}
//前置++ 先++ 再返回
void test01()
{
MyInteger myInt;
cout << ++myInt << endl;
cout << myInt << endl;
}
//后置++ 先返回 再++
void test02()
{
MyInteger myInt;
cout << myInt++ << endl;
cout << myInt << endl;
}
int main()
{
//test01();
test02();
system("pause");
return 0;
}
总结： 前置递增返回引用，后置递增返回值
#include
using namespace std;
//赋值运算符重载
class Person
{
public:
Person(int age)
{
//将年龄数据开辟到堆区
m_Age = new int(age);
}
//重载赋值运算符
Person& operator=(Person &p)
{
//应该先判断是否有属性在堆区，如果有先释放感觉，然后再深拷贝
if (m_Age != NULL)
{
delete m_Age;
m_Age = NULL;
}
//编译器提供的代码是浅拷贝
//m_Age = p.m_Age;
//提供深拷贝 解决浅拷贝的问题
m_Age = new int(*p.m_Age);
//返回对象自身
return *this;
}
~Person()
{
if (m_Age != NULL)
{
delete m_Age;
m_Age = NULL;
}
}
//年龄的指针
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();
//int a = 10;
//int b = 20;
//int c = 30;
//c = b = a;
//cout << "a = " << a << endl;
//cout << "b = " << b << endl;
//cout << "c = " << c << endl;
system("pause");
return 0;
}
#include
using namespace std;
#include
//重载关系运算符
class Person
{
public:
Person(string name, int age)
{
this->m_Name = name;
this->m_Age = age;
};
//重载 == 号
bool operator==(Person & p)
{
if (this->m_Name == p.m_Name && this->m_Age == p.m_Age)
{
return true;
}
else
{
return false;
}
}
bool operator!=(Person & p)
{
if (this->m_Name == p.m_Name && this->m_Age == p.m_Age)
{
return false;
}
else
{
return true;
}
}
string m_Name;
int m_Age;
};
void test01()
{
//int a = 0;
//int b = 0;
Person a("孙悟空", 18);
Person b("孙悟空", 18);
if (a == b)
{
cout << "a和b相等" << endl;
}
else
{
cout << "a和b不相等" << endl;
}
if (a != b)
{
cout << "a和b不相等" << endl;
}
else
{
cout << "a和b相等" << endl;
}
}
int main() {
test01();
system("pause");
return 0;
}
#include
using namespace std;
#include
//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 text)
{
cout << text << endl;
}
};
void myFunc2(string text)
{
cout << text << endl;
}
void test01()
{
//重载的（）操作符 也称为仿函数
MyPrint myFunc;
myFunc("hello world");//由于使用起来非常类似于函数调用，因此称为仿函数
myFunc2("hello world");
}
//仿函数非常灵活，没有固定的写法
//加法类
class MyAdd
{
public:
int operator()(int v1, int v2)
{
return v1 + v2;
}
};
void test02()
{
MyAdd add;
int ret = add(10, 10);
cout << "ret = " << ret << endl;
//匿名函数对象调用
cout << "MyAdd()(100,100) = " << MyAdd()(100, 100) << endl;
}
int main() {
test01();
test02();
system("pause");
return 0;
}