程序代码:

#include <iostream>

using namespace std;

class Complex   
{
public:
      Complex( )//定义默认构造函数初始化复数
      {
          real=0;
          imag=0;
      }      
     
      //使用初始化表初始化复数
      Complex(double r, double i):real(r),imag(i){}
     
      Complex operator+(Complex &c2);//复数的加法
      Complex operator-(Complex &c2);//复数的减法
      Complex operator*(Complex &c2);//复数的乘法
      Complex operator/(Complex &c2);//复数的除法

      //重载<<运算符实现输出复数
      friend ostream&  operator <<(ostream& output, Complex& c);

       //重载>>运算符实现输入复数
      friend istream&  operator >>(istream& input, Complex& c);

private:
      double real;//复数的实部
      double imag;//复数的虚部
};

//复数的加法
Complex Complex::operator+(Complex &c2)
{
    Complex c3;

    c3.real  = real + c2.real;
    c3.imag  = imag + c2.imag;

    return c3;
}

//复数的减法
Complex Complex::operator-(Complex &c2)
{
    Complex c3;

    c3.real  = real - c2.real;
    c3.imag  = imag - c2.imag;

    return c3;
}

//复数的乘法
Complex Complex::operator*(Complex &c2)
{
    Complex c3;

    c3.real = real*c2.real - imag * c2.imag;
    c3.imag = real*c2.imag + imag * c2.real;

    return c3;
}

//复数的除法
Complex Complex::operator/(Complex &c2)
{  
    Complex c3;

    c3.real = (real * c2.real + imag * c2.imag) / (c2.real*c2.real + c2.imag * c2.imag);

    c3.imag = (imag * c2.real - real * c2.imag) / (c2.real*c2.real + c2.imag * c2.imag);

    return c3;
}

//重载>>运算符实现输入复数
istream&  operator >>(istream& input, Complex& c)
{
    int a, b;
    char sign, i;

    do
    {
        cout<<"请输入一个复数,以(a+bi或a-bi)的形式输入:";
        input>>a>>sign>>b>>i;

    }while(!(('+' == sign || '-' == sign) && 'i' == i));

   c.real = a;
   c.imag = ('+' == sign) ? b : -b;

   return input;
}

//重载<<运算符实现输出复数
ostream&  operator <<(ostream& output, Complex& c)
{
    int num = c.imag;

    if(num>0)
    {
        output<<c.real<<"+"<<c.imag<<"i"<<endl;
    }
    else
    {
        output<<c.real<<c.imag<<"i"<<endl;
    }

    return output;
}

void main( )
{
    //定义三个复数
    Complex c1, c2, c3;

    cout<<"请输入一个复数:";
    cin>>c1;

    cout<<"请输入一个复数:";
    cin>>c2;

    //打印第一个复数
    cout<<"c1 = ";
    cout<<c1;
   
    //打印第二个复数
    cout<<"c2 = ";
    cout<<c2;

    //两个复数相加
    c3 = c1 + c2;
    cout<<"c1 + c2 = ";
    cout<<c3;

    //两个复数想减
    c3 = c1 - c2;
    cout<<"c1 - c2 = ";
   cout<<c3;

    //两个复数相乘
    c3 = c1 * c2;
    cout<<"c1 * c2 = ";
    cout<<c3;

    //两个复数相除
    c3 = c1 / c2;
    cout<<"c1 / c2 = ";
    cout<<c3;

    system("pause");
}

执行结果: