複数クラスの実装

#include<iostream>
using namespace std;
class Complex
{
public:
	// 
	void Display()
	{
		cout<<_real<<"+"<<_image<<"i"<<endl;
	}
	// 
	Complex(double x=0.0,double y=0.0)
	{
		_real=x;
		_image=y;	
	}
	// 
	~Complex()
	{
		;//cout<<" "<<endl;
	}
	// 
	Complex(const Complex& c1)
	{
		if(this!=&c1)
		{
			_real=c1._real;
			_image=c1._image;
		}
		cout<<" "<<endl;
	}
	// 
	Complex operator+(Complex &c1)
	{
		Complex c2;
		c2._real=_real+c1._real;
		c2._image=_image+c1._image;
		return c2;
	}
	// 
	Complex operator-(Complex &c1)
	{
		Complex c2;
		c2._real=_real-c1._real;
		c2._image=_image-c1._image;
		return c2;
	}
	// 
	Complex operator *(Complex &c1)
	{
		Complex c2;
		c2._real=_real*c1._real;
		c2._image=_image*c1._image;
		return c2;
	}
	// 
	Complex operator/(Complex &c1)
	{
		Complex c2;
		c2._real=_real/c1._real;
		c2._image=_image/c1._image;
		return c2;
	}
	// 
	Complex& operator+=(const Complex &c1)
	{
		_real+=c1._real;
		_image+=c1._image;
		return *this;
	}
	// 
	Complex& operator-=(const Complex &c1)
	{
		_real-=c1._real;
		_image-=c1._image;
		return *this;
	}
	// ++
	Complex& operator ++()
	{
		++_real;
		++_image;
		return *this;
	}
	// ++
	Complex operator ++(int)
	{
		Complex tmp(*this);
		this->_real++;
		this->_image++;
		return tmp;
	}
	// --
	Complex& operator--()
	{
		_real--;
		_image--;
		return *this;
	}
	// --
	Complex operator--(int)
	{
		Complex tmp(*this);
		this->_real--;
		this->_image--;
		return tmp;
	}
	//    c1>c2
	Complex()
	{
		;
	}
private:
	double _real;
	double _image;
};
int main()
{
	Complex c1(1.0,2.0),c2(2.0,2.0),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();
	c1+=c2;
	cout<<"c1=";
	c1.Display();
	c1-=c2;
	cout<<"c1=";
	c1.Display();*/
	c3=c2+(--c1);
	cout<<"c3=";
	c3.Display();
	cout<<"c1=";
	c1.Display();
	system("pause");
	return 0;
}