C++运算符重载
文章目录
一、C++为什么要进行运算符重载
重载就是给已有的赋予新的含义。函数重载是可以让一个函数名有多种功能，在不同的情况下进行不同的操作。运算符的重载
就是给已有的运算符定义新的含义，比如对+进行重载，可以达到类的加法。实际上我们已经在使用这些运算符的重载，<<既是位移运算符，又可以配合 cout 向控制台输出数据。C++ 本身已经对这些运算符进行了重载。
二、C++运算符重载的限制
1.不能重载的运算符
作用域限定符 (::)
直接成员访问运算符 (.)
条件表达式运算符(?:)
字节长度运算符(sizeof)
类型信息运算符(typedef)
类型信息运算符(typeid)
2.基本类型的运算符无法重载
int a,b
a + b;
int operator +(int& a,int& b)
(
return a+b;
)
3.无法通过操作符重载来改变运算符的优先级
4.不能改变操作数的个数
5,不能发明新的运算符
三、+ - * / 运算符重载
实现的部分代码：
#include <iostream>
#include <cmath>
using namespace std;
//复数类
class Complex{
public: //构造函数
Complex(double real = 0.0, double imag = 0.0): m_real(real), m_imag(imag){ }
public: //运算符重载
//以全局函数的形式重载
friend Complex operator+(const Complex &c1, const Complex &c2);
friend Complex operator-(const Complex &c1, const Complex &c2);
friend Complex operator*(const Complex &c1, const Complex &c2);
friend Complex operator/(const Complex &c1, const Complex &c2);
//以成员函数的形式重载
Complex & operator+=(const Complex &c);
Complex & operator-=(const Complex &c);
Complex & operator*=(const Complex &c);
Complex & operator/=(const Complex &c);
private:
double m_real; //实部
double m_imag; //虚部
};
//重载+运算符
Complex operator+(const Complex &c1, const Complex &c2){
Complex c;
c.m_real = c1.m_real + c2.m_real;
c.m_imag = c1.m_imag + c2.m_imag;
return c;
}
//重载-运算符
Complex operator-(const Complex &c1, const Complex &c2){
Complex c;
c.m_real = c1.m_real - c2.m_real;
c.m_imag = c1.m_imag - c2.m_imag;
return c;
}
//重载*运算符 (a+bi) * (c+di) = (ac-bd) + (bc+ad)i
Complex operator*(const Complex &c1, const Complex &c2){
Complex c;
c.m_real = c1.m_real * c2.m_real - c1.m_imag * c2.m_imag;
c.m_imag = c1.m_imag * c2.m_real + c1.m_real * c2.m_imag;
return c;
}
//重载/运算符 (a+bi) / (c+di) = [(ac+bd) / (c²+d²)] + [(bc-ad) / (c²+d²)]i
Complex operator/(const Complex &c1, const Complex &c2){
Complex c;
c.m_real = (c1.m_real*c2.m_real + c1.m_imag*c2.m_imag) / (pow(c2.m_real, 2) + pow(c2.m_imag, 2));
c.m_imag = (c1.m_imag*c2.m_real - c1.m_real*c2.m_imag) / (pow(c2.m_real, 2) + pow(c2.m_imag, 2));
return c;
}
//重载+=运算符
Complex & Complex::operator+=(const Complex &c){
this->m_real += c.m_real;
this->m_imag += c.m_imag;
return *this;
}
//重载-=运算符
Complex & Complex::operator-=(const Complex &c){
this->m_real -= c.m_real;
this->m_imag -= c.m_imag;
return *this;
}
//重载*=运算符
Complex & Complex::operator*=(const Complex &c){
this->m_real = this->m_real * c.m_real - this->m_imag * c.m_imag;
this->m_imag = this->m_imag * c.m_real + this->m_real * c.m_imag;
return *this;
}
//重载/=运算符
Complex & Complex::operator/=(const Complex &c){
this->m_real = (this->m_real*c.m_real + this->m_imag*c.m_imag) / (pow(c.m_real, 2) + pow(c.m_imag, 2));
this->m_imag = (this->m_imag*c.m_real - this->m_real*c.m_imag) / (pow(c.m_real, 2) + pow(c.m_imag, 2));
return *this;
}
int main(){
Complex c1(25, 35);
Complex c2(10, 20);
Complex c3(1, 2);
Complex c4(4, 9);
Complex c5(34, 6);
Complex c6(80, 90);
Complex c7 = c1 + c2;
Complex c8 = c1 - c2;
Complex c9 = c1 * c2;
Complex c10 = c1 / c2;
cout<<"c7 = "<<c7.real()<<" + "<<c7.imag()<<"i"<<endl;
cout<<"c8 = "<<c8.real()<<" + "<<c8.imag()<<"i"<<endl;
cout<<"c9 = "<<c9.real()<<" + "<<c9.imag()<<"i"<<endl;
cout<<"c10 = "<<c10.real()<<" + "<<c10.imag()<<"i"<<endl;
c3 += c1;
c4 -= c2;
c5 *= c2;
c6 /= c2;
cout<<"c3 = "<<c3.real()<<" + "<<c3.imag()<<"i"<<endl;
cout<<"c4 = "<<c4.real()<<" + "<<c4.imag()<<"i"<<endl;
cout<<"c5 = "<<c5.real()<<" + "<<c5.imag()<<"i"<<endl;
cout<<"c6 = "<<c6.real()<<" + "<<c6.imag()<<"i"<<endl;
return 0;
}