自考新教材-p166

源程序：

#include<iostream>
#include<string>
#include<cstdlib>
using namespace std;

class myComplex
{
private:
double real,imag;
public:
myComplex():real(0),imag(0){}
myComplex(double r,double i):real(r),imag(i){}
ostream & operator<<(ostream & os); //成员函数，插入
friend istream & operator>>(istream & is,myComplex & c); //友元，提取
};

ostream & myComplex::operator<<(ostream & os) //类的成员函数
{
if(this->imag>=0)
os<<this->real<<"+"<<this->imag<<"i"; //以a+bi的形式输出
else
os<<this->real<<"+"<<(-this->imag)<<"i";
return os;
}

istream & operator>>(istream & is,myComplex & c)
{
string s;
is>>s; //将a+bi作为字符串读入，a+bi中间不能有空格
int pos = s.find("+",0); //查找虚部
if(pos==-1)
pos=s.find("-",1); //虚部为负数时
string sReal=s.substr(0,pos); //分离出代表实部的字符串
c.real=atof(sReal.c_str()); //atof()能将参数内容转换成浮点数
sReal=s.substr(pos,s.length()-pos-1); //分离出代表虚部的字符串
c.imag=atof(sReal.c_str());
return is;
}

int main()
{
myComplex c,c1;
int n;
cout<<"请输入两个复数([-]a+-bi)和一个整数，以空格分隔"<<endl;
cin>>c>>c1>>n;
cout<<(c<<cout<<",")<<","<<n<<endl; //注意调用的形式
return 0;
}

 运行结果：