侯捷老师的C++代码： 基于对象之一 无指针类型 复数类实现

//makefile

cc = g++
prom = complex
obj = complex.o
$(prom):$(obj)
    rm -rf *.exe;
    $(cc) -o $(prom) $(obj)

//complex.h
#ifndef __COMPLEX__
#define __COMPLEX__

class complex{
    public:
        complex(double r = 0, double i = 0)
            :re(r) , im(i){}
        complex& operator+=(const complex&);
        double real() const {return re;}
        double ima() const {return im;}
    private:
        double re, im;
        friend complex& __doapl(complex* , const complex &);
};

inline complex& __doapl(complex* ths, const complex& r)
{
    ths->re += r.re;
    ths->im += r.im;
    return *ths;
}


inline complex& complex::operator +=(const complex& rhs)
{
    return __doapl(this, rhs);
}


inline double real(const complex& r)
{
    return r.real();
}

inline double im(const complex& r)
{
    return r.ima();
}


inline complex
operator +(const complex& l, const complex& r)
{
    return complex(real(l) + real(r),
            im(l) + im(r));
}

#include <iostream>
using namespace std;

ostream & operator << (ostream& os , const complex &r)
{
    os << "(" << real(r) << "," << im(r) << ")";
}


#endif

//complex.cpp

#include "complex.h"

int main()
{
    complex c1;
    cout << c1 << endl;
    complex c2(1,3);
    cout << c2 << endl;
    c2+=c2;
    cout << c2 << endl;
    return 0;
    
}