arithmetic function for complex numbers-c++

C++ Program to Add ,Substract,Multiply and Divide Complex Numbers Using Operator Overloading

 #include<iostream.h>  
 #include<conio.h>  
 #include<string.h>  
 #include<stdio.h>  
 class complex  
 {  
  int i,r;  
  public:  
  void read()  
  {  
  cout<<"\nEnter Real Part:";  
  cin>>r;  
  cout<<"Enter Imaginary Part:";  
  cin>>i;  
  }  
  void display()  
  {  
  cout<<"\n= "<<r<<"+"<<i<<"i";  
  }  
  complex operator+(complex a2)  
  {  
  complex a;  
  a.r=r+a2.r;  
  a.i=i+a2.i;  
  return a;  
  }  
  complex operator-(complex a2)  
  {  
  complex a;  
  a.r=r-a2.r;  
  a.i=i-a2.i;  
  return a;  
  }  
  complex operator*(complex a2)  
  {  
  complex a;  
  a.r=(r*a2.r)-(i*a2.i);  
  a.i=(r*a2.i)+(i*a2.r);  
  return a;  
  }  
  complex operator/(complex a2)  
  {  
  complex a;  
  a.r=((r*a2.r)+(i*a2.i))/((a2.r*a2.r)+(a2.i*a2.i));  
  a.i=((i*a2.r)-(r*a2.i))/((a2.r*a2.r)+(a2.i*a2.i));  
  return a;  
  }  
 };  
 void main()  
 {  
 int ch;  
 clrscr();  
 complex a,b,c;  
 do  
 {  
  cout<<"\n1.Addition 2.Substraction";  
  cout<<" 3.Mulitplication 4.Division 5.Exit\n";  
  cout<<"\nEnter the choice :";  
  cin>>ch;  
  switch(ch)  
  {  
  case 1:  
       cout<<"\nEnter The First Complex Number:";  
       a.read();  
       a.display();  
       cout<<"\nEnter The Second Complex Number:";  
       b.read();  
       b.display();  
       c=a+b;  
       c.display();  
       break;  
  case 2:  
       cout<<"\nEnter The First Complex Number:";  
       a.read();  
       a.display();  
       cout<<"\nEnter The Second Complex Number:";  
       b.read();  
       b.display();  
       c=b-a;  
       c.display();  
       break;  
  case 3:  
       cout<<"\nEnter The First Complex Number:";  
       a.read();  
       a.display();  
       cout<<"\nEnter The Second Complex Number:";  
       b.read();  
       b.display();  
       c=a*b;  
       c.display();  
       break;  
  case 4:  
       cout<<"\nEnter The First Complex Number:";  
       a.read();  
       a.display();  
       cout<<"\nEnter The Second Complex Number:";  
       b.read();  
       b.display();  
       c=a/b;  
       c.display();  
       break;  
  }  
  }while(ch!=5);  
 getch();  
 }