正确代码：
#include<iostream>
using namespace std;
class Complex
{
friend ostream &operator << (ostream &out,const Complex &c);
private:
int m_a;
int m_b;
public:
Complex();
Complex(int a,int b);
void print();
Complex operator + (Complex &c1);
Complex operator ++(int); //后置++
Complex &operator ++();
// ostream &operator << (ostream &out,Complex &c); 不能改
};
Complex::Complex()
{
m_a=1;
m_b=1;
}
Complex::Complex(int a,int b)
{
m_a=a;
m_b=b;
}
void Complex::print()
{
cout<<m_a<<"+"<<m_b<<"i"<<endl;
}
Complex Complex:: operator +(Complex &c1) //通过成员函数的方式重载 +
{
this->m_a=c1.m_a+this->m_a;
this->m_b=c1.m_b+this->m_b;
return *this;
}
ostream& operator << (ostream &out,const Complex &c)
{
out<<c.m_a<<"+"<<c.m_b<<"i"<<endl;
return out;
}
Complex Complex:: operator ++(int)
{
Complex tmp=*this;
m_a++;
m_b++;
return tmp;
}
Complex &Complex::operator ++()
{
this->m_a++;
this->m_b++;
return *this;
}
int main()
{
Complex c1(1,2);
Complex c2(2,3);
Complex c3(3,4);
Complex c4;
// c1.operator +(c2);
// c1.print();
cout<<"**********"<<endl;
// c4=c2+c3;
c4.print();
cout<<"************************"<<endl;
cout<< c1++ <<endl;
cout<< ++c1 <<endl;
return 0;
}在编译运行过程中第68，69行一直有错误，原因是<<运算符不支持c1++的格式，第5行和第38行Complex前没有加 const修饰。（上图代码已改正）
另外需要注意的是，第50行的&应该加在第二个Complex前面而不是operator前面。
在第14，15行函数声明中，14行后置++函数声明中operator前没有加&而第15行前置++函数声明中加了，原因是前置++返回引用，而后置++返回对象本身。
14行后置++中括号内的int 为占位字节。必须要写。
运行结果:
