基本运算符的重载（复数类）

基本运算符的重载（类操作符）

#include<iostream>
using namespace std;
class Complex 
{
public:
    Complex(){real=0;imag=0;}
    Complex(double r,double i){real=r; imag=i;}
    Complex operator+(const Complex &c2);
    Complex operator-(const Complex &c2);
    Complex operator*(const Complex &c2);
    Complex operator/(const Complex &c2);
    void display();
private:
    double real;
    double imag;
};
Complex Complex::operator+(const Complex &c2)
{
	Complex result;
	result.real=real+c2.real;
	result.imag=imag+c2.imag;
	return result;
}
Complex	Complex::operator-(const Complex &c2)
{
	Complex result;
	result.real=real+c2.real;
	result.imag=imag+c2.imag;
	return result;
}
Complex Complex::operator*(const Complex &c2)
{
	Complex result;
	result.real=real*c2.real-imag*c2.imag;
	result.imag=imag*c2.real+real*c2.imag;
	return result;
}
Complex Complex::operator/(const Complex &c2)
{
	Complex result;
	double a,b,c;
	a=real*c2.real+imag*c2.imag;
	b=imag*c2.real-real*c2.imag;
	c=c2.real*c2.real+c2.imag*c2.imag;
	result.real=a/c;
	result.imag=b/c;
//	result.real=(real*c2.real+imag*c2.imag)/(c2.real*c2.real+c2.imag*c2.imag);
//	result.imag=(imag*c2.real-real*c2.imag)/(c2.real*c2.real+c2.imag*c2.imag);
	return result;
}
void Complex::display()
{
	cout<<real;
	if(imag>0)
		cout<<"+"<<imag<<"i"<<endl;
	if(imag<0)
		cout<<imag<<"i"<<endl;
}
int main()
{
    Complex c1(3,4),c2(5,-10),c3;
    cout<<"c1=";
    c1.display();
    cout<<"c2=";
    c2.display();
    c3=c1+c2;
    cout<<"c1+c2=";
    c3.display();
    c3=c1-c2;
    cout<<"c1-c2=";
    c3.display();
    c3=c1*c2;
    cout<<"c1*c2=";
    c3.display();
    c3=c1/c2;
    cout<<"c1/c2=";
    c3.display();
    return 0;
}

运行结果：

基本运算符的重载（全局操作符）

#include<iostream>
using namespace std;
class Complex 
{
public:
    Complex(){real=0;imag=0;}
    Complex(double r,double i){real=r; imag=i;}
    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);
    void display();
private:
    double real;
    double imag;
};
Complex operator+(const Complex &c1,const Complex &c2)
{
	Complex result;
	result.real=c1.real+c2.real;
	result.imag=c1.imag+c2.imag;
	return result;
}
Complex	operator-(const Complex &c1,const Complex &c2)
{
	Complex result;
	result.real=c1.real+c2.real;
	result.imag=c1.imag+c2.imag;
	return result;
}
Complex operator*(const Complex &c1,const Complex &c2)
{
	Complex result;
	result.real=c1.real*c2.real-c1.imag*c2.imag;
	result.imag=c1.imag*c2.real+c1.real*c2.imag;
	return result;
}
Complex operator/(const Complex &c1,const Complex &c2)
{
	Complex result;
	double a,b,c;
	a=c1.real*c2.real+c1.imag*c2.imag;
	b=c1.imag*c2.real-c1.real*c2.imag;
	c=c2.real*c2.real+c2.imag*c2.imag;
	result.real=a/c;
	result.imag=b/c;
	return result;
}
void Complex::display()
{
	cout<<real;
	if(imag>0)
		cout<<"+"<<imag<<"i"<<endl;
	if(imag<0)
		cout<<imag<<"i"<<endl;
}
int main()
{
    Complex c1(3,4),c2(5,-10),c3;
    cout<<"c1=";
    c1.display();
    cout<<"c2=";
    c2.display();
    c3=c1+c2;
    cout<<"c1+c2=";
    c3.display();
    c3=c1-c2;
    cout<<"c1-c2=";
    c3.display();
    c3=c1*c2;
    cout<<"c1*c2=";
    c3.display();
    c3=c1/c2;
    cout<<"c1/c2=";
    c3.display();
    return 0;
}

运行结果：

在没有接触过这个概念的时候自己还是不好理解他，但是在最后实际操作之后还是十分简单。在加了frien声明的时候在vc++6.0的编译环境中，显示的并没有成功。出现了错误——

fatal error C1001: INTERNAL COMPILER ERROR
        (compiler file 'msc1.cpp', line 1786)
         Please choose the Technical Support command on the Visual C++
         Help menu, or open the Technical Support help file for more information

但将编译环境改成vs2012之后就显示编译成功。

之后为了在书中查到，在VC++6.0当中并没有实现完全的C++机制，它所提供的不带后缀.h的头文件不支持将C++类库中的对象（ostream和istream）作为友元函数的参数，但是VC++6.0所提供的老形式的带后缀.h的头文件支持这样的功能。