C++操作符重载

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//成员函数操作符重载
inline complex& __doapl(complex *this,const complex&r)
{
return *this;
}
inline complex & complex::operator+=(const complex& r)
{
return _doapl(this,r);
}
C3+=C2+=C1; //使用者使用连串使用的方式 返回reference &,所以不返回void 
inline double imag(const complex&x) //传引用比较快
{
return x.imag();
}
//非成员函数操作符重载.return by value不能返回return by reference,返回的是local object.
inline complex operator +(const complex& x,const complex& y)
{
return complex(real(x)+real(y),
//typename()创建临时对象
imag(x)+imag(y));
}
inline complex operator +(const complex& x)
{
return x;
}
inline complex operator - (const complex &x)
{
return complex(-real(x),-image(x));
}
inline bool operator !=(const complex &x,
const complex &y)
{
return real(x)!=real(y)
||imag(x)!=imag(y);
}
#include<iostream>
inline complex conj(const complex&x)
{
return complex(real(x),-imag(x));
}
ostream & operator<<(ostream &os,const complex&)
{
return os<<'('<<real(x)<<','<<imag(x)<<')';
}
complex c1(2,1);
cout<<conj(c1);-->(2,-1)
cout<<c1<<conj(c1);-->(2,1)(2,-1) //返回值为ostream
class complex
{
public:
complex (double r=0,double i=0)
:re(r),im(i)
{}
complex &operator +=(const complex&);
double real() const { return re; }
double imag() const { return im; }
private://数据放到private里面
double re;
double im;
friend complex& _doapl(complex *,const complex&);
};
#ifndef __COMPLEX__
#define __COMPLEX__
class complex
{
public:
complex(double r=0,double i=0)
:re(r),im(i)//初值列
{}
complex& operator+=(const complex&);
inline double real() const { return re; }
inline double imag() const { return im; }
private:
double re,im;
friend complex& __doapl(complex *,const complex&);
}
#endif
inline complex& __doapl(complex *ths,const complex& r)//告诉编译器去inline
{
ths->re+=r.re;
ths->im+=r.im;
return *ths;
}
inline complex& complex::operator +=(const complex& r)
{
return __doapl(this,r);
}
inline complex operator + (const complex & x,const complex & y)//return by value
{
return complex(real(x)+real(y),
//typename()创建临时对象
imag(x)+imag(y));
}
#include <iosteam>
inline ostream& operator <<(ostream& os,const complex& x)
{
return os<<'('<<real(x)<<','<<imag(x)<<')';
}