C++ Primer Plus学习笔记之运算符重载

#include
  
   

using namespace std;

class Complex
{
	public:
		Complex(double r=0,double i=0)
		{
			re=r;
			im=i;
		}
		Complex operator+(const Complex& obj);
		Complex operator!();
		void Display();
	private:
		double re;
		double im;
};

Complex Complex::operator+(const Complex& obj)
{
	Complex temp;
	temp.re=re+obj.re;
	temp.im=im+obj.im;
	return temp;
}

Complex Complex::operator!()
{
	Complex temp;
	temp.re=re;
	temp.im=-im;
	return temp;
}

void Complex::Display()
{
	cout<
   
    0) cout<<"+"<
    
     友元函数重载 
     
#include
      
       

using namespace std;

class Complex
{
	public:
		Complex(double r=0,double i=0)
		{
			re=r;
			im=i;
		}
		friend Complex operator+(const Complex& obj1,const Complex& obj2);
		Complex operator!();
		void Display();
	private:
		double re;
		double im;
};

Complex operator+(const Complex& obj1,const Complex& obj2)
{
	Complex temp;
	temp.re=obj1.re+obj2.re;
	temp.im=obj1.im+obj2.im;
	return temp;
}

Complex Complex::operator!()
{
	Complex temp;
	temp.re=re;
	temp.im=-im;
	return temp;
}

void Complex::Display()
{
	cout<
       
        0) cout<<"+"<
        
         对于成员函数重载，由于obj3=27+obj1的显示调用为obj3=27.operator+(obj1)，而27不是Complex类型，因此编译器不能调用Complex的operator+()重载运算符完成加法操作； 对于友元函数重载，由于obj3=27+obj1的调用通过有一个参数缺省的构造函数Complex(double r=0,double i=0)，
         系统可以自动将27转换为Complex(27)对象，因此编译通过； 由此可知，成员函数仅仅能为一个实际对象所调用，友元无此限制。因此若运算符的操作需要修改类对象的状态，则它应该是成员函数，而不应该是友元。相反，如果运算符的操作数(尤其是第一个操作数)希望有隐式类型转换，则该运算符重载必须用友元函数，而不是成员函数。 2，重载++的前缀和后缀 成员函数重载 
         
#include
          






           

using namespace std;

class Complex
{
	public:
		Complex(double r=0,double i=0)
		{
			re=r;
			im=i;
		}
		friend Complex operator+(const Complex& obj1,const Complex& obj2);
		Complex& operator++();//前缀方式
		Complex operator++(int);//后缀方式
		Complex operator!();
		void Display();
	private:
		double re;
		double im;
};

Complex operator+(const Complex& obj1,const Complex& obj2)
{
	Complex temp;
	temp.re=obj1.re+obj2.re;
	temp.im=obj1.im+obj2.im;
	return temp;
}

Complex& Complex::operator++()
{
	re++;
	im++;
	return *this;
}

Complex Complex::operator++(int)//int为占位符
{
	Complex temp(*this);//拷贝构造函数
	re++;
	im++;
	return temp;
}

Complex Complex::operator!()
{
	Complex temp;
	temp.re=re;
	temp.im=-im;
	return temp;
}

void Complex::Display()
{
	cout<
           
            0) cout<<"+"<
            
             #include
             
               using namespace std; class Complex { public: Complex(double r=0,double i=0) { re=r; im=i; } friend Complex operator+(const Complex& obj1,const Complex& obj2); friend Complex& operator++(Complex& obj);//前缀方式 friend Complex operator++(Complex& obj,int);//后缀方式 Complex operator!(); void Display(); private: double re; double im; }; Complex operator+(const Complex& obj1,const Complex& obj2) { Complex temp; temp.re=obj1.re+obj2.re; temp.im=obj1.im+obj2.im; return temp; } Complex& operator++(Complex& obj) { obj.re++; obj.im++; return obj; } Complex operator++(Complex& obj,int)//int为占位符 { Complex temp(obj);//拷贝构造函数 obj.re++; obj.im++; return temp; } Complex Complex::operator!() { Complex temp; temp.re=re; temp.im=-im; return temp; } void Complex::Display() { cout<
              
               0) cout<<"+"<
               
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