Operator Overloading in C++ to add,substract,multiply and divide two Complex Numbers

Operator Overloading is a technique of polymorphism by which an operator(+,- etc) can be used to do different types of operations. eg:+ can be used to add two integers say a and b using sum=a+b similarly two floating point numbers say fa,fb by fs=fa+fb. In this example +,-,*,- operators are overloaded to add,subtract, multiply and divide two complex numbers. 

#include<iostream.h> 

 #include<conio.h> 

 class complex 

 { 

 int a,b; 

 public: 

 void read() 

 { 

 cout<<"\n\nEnter the REAL PART : "; 

 cin>>a; 

 cout<<"\n\nEnter the IMAGINARY PART : "; 

 cin>>b; 

 } 

 complex operator +(complex c2) 

 { 

 complex c3; 

 c3.a=a+c2.a; 

 c3.b=b+c2.b; 

 return c3; 

 } 

 complex operator -(complex c2) 

 { 

 complex c3; 

 c3.a=a-c2.a; 

 c3.b=b-c2.b; 

 return c3; 

 } 

 complex operator *(complex c2) 

 { 

 complex c3; 

 c3.a=(a*c2.a)-(b*c2.b); 

 c3.b=(b*c2.a)+(a*c2.b); 

 return c3; 

 } 

 complex operator /(complex c2) 

 { 

 complex c3; 

 c3.a=((a*c2.a)+(b*c2.b))/((c2.a*c2.a)+(c2.b*c2.b)); 

 c3.b=((b*c2.a)-(a*c2.b))/((c2.a*c2.a)+(c2.b*c2.b)); 

 return c3; 

 } 

 void display() 

 { 

 cout<<a<<"+"<<b<<"i"; 

 } 

 }; 

 void main() 

 { 

 complex c1,c2,c3; 

 int choice,cont; 

 do 

 { 

 clrscr(); 

 cout<<"\t\tCOMPLEX NUMBERS\n\n1.ADDITION\n\n2.SUBTRACTION\n\n3.MULTIPLICATION\n\n4.DIVISION"; 

 cout<<"\n\nEnter your choice : "; 

 cin>>choice; 

 if(choice==1||choice==2||choice==3||choice==4) 

 { 

 cout<<"\n\nEnter the First Complex Number"; 

 c1.read(); 

 cout<<"\n\nEnter the Second Complex Number"; 

 c2.read(); 

 } 

 switch(choice) 

 { 

 case 1     : c3=c1+c2; 

            cout<<"\n\nSUM = "; 

            c3.display(); 

            break; 

 case 2     : c3=c1-c2; 

            cout<<"\n\nResult = "; 

            c3.display(); 

            break; 

 case 3 : c3=c1*c2; 

            cout<<"\n\nPRODUCT = "; 

            c3.display(); 

            break; 

 case 4     : c3=c1/c2; 

            cout<<"\n\nQOUTIENT = "; 

            c3.display(); 

            break; 

 default     : cout<<"\n\nUndefined Choice"; 

 } 

 cout<<"\n\nDo You Want to Continue?(1-Y,0-N)"; 

 cin>>cont; 

 }while(cont==1); 

 getch(); 

 }