C++学习（5）

关于类的运算符重载：

分为两种： 1）将运算符重载为类的友元函数

　　　　　　2）将运算符重在为类的成员函数

一：

//friend 函数类型   operator 运算符(形参表){}
//通过重载 ，进行复数运算
#include <iostream>
using namespace std;

class Complex
{
    private:
        double real;
        double image;
    public:
    Complex(double real=0.0,double image=0.0)
    {
        this->real=real;
        this->image=image;
    }
    void display()
    {
        cout<<"("<<real<<","<<image<<")"<<endl;
    }
    friend Complex operator + (Complex A, Complex B)
    {
        return Complex (A.real+B.real,A.image+B.image);
    }
    friend Complex operator - (Complex A, Complex B);
    friend Complex operator - (Complex A);      //  重载取负为友元函数
    friend Complex operator ++ (Complex &A);    //  重载前置++为友元函数
    friend Complex operator ++ (Complex &A, int); // 重载后置++为友元函数
};

Complex operator -(Complex A,Complex B)
{
    return Complex(A.real-B.real,A.image-B.image);
}

Complex operator -(Complex A)
{
    return Complex(-A.real,-A.image);
}

Complex operator ++(Complex &A)
{
    return Complex(++A.real,A.image);
}

Complex operator ++(Complex &A,int)
{
    return Complex(A.real++,A.image);
}

int main()
{
    Complex A(100.0,200.0),B(-10.0,20.0),C;
    cout<<"A=", A.display();
    cout<<"B=", B.display();
    C=A+B;
    cout<<"C=A+B=", C.display();
    C=A-B;
    cout<<"C=A-B=", C.display();
    C=-A+B;
    cout<<"C=-A+B", C.display();
    C=A++;
    cout<<"C=A++, C=", C.display();
    C=++A;
    cout<<"C=++A, C=", C.display();
    C=A+5;
    C.display();
    return 0;
}

二：

//重载为类的成员函数
// 返回类型 类名::operator 运算符（形参表）
#include <iostream>
using namespace std;
class Complex
{
    private:
        double real;
        double image;
    public:
        Complex(double real=0.0,double image=0.0)
        {
            this->real=real;
            this->image=image;
        }
        void display()
        {
            cout<<"("<<real<<","<<image<<")"<<endl;
        }
        Complex operator + (Complex B);
        Complex operator - (Complex B);
        Complex operator - ();          //取负重载成员函数
        Complex operator ++ ();         //前置++重载成员函数
        Complex operator ++ (int);      //后置--重载成员函数

};
Complex Complex::operator + (Complex B)
{
    return Complex(real+B.real,image+B.image);
}

Complex Complex::operator - (Complex B)
{
    return Complex(real+B.real,image+B.image);
}

Complex Complex::operator - ()
{
    return Complex(-real,-image);
}

Complex Complex::operator ++()
{
    return Complex(++real,image);
}

Complex Complex::operator ++(int)
{
    return Complex(real++,image);
}

int main()
{
    Complex A(100.0,200.0),B(-10.0,20.0),C;
    cout<<"A=", A.display();
    cout<<"B=", B.display();
    C=A+B;
    cout<<"C=A+B=", C.display();
    C=A-B;
    cout<<"C=A-B=", C.display();
    C=-A+B;
    cout<<"C=-A+B", C.display();
    C=A++;
    cout<<"C=A++, C=", C.display();
    C=++A;
    cout<<"C=++A, C=", C.display();
    C=A+5;
    C.display();
    return 0;
}