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. First a class named complex is created which has overloaded operators like + specified by a function 'complex operator +(complex c2)' which can used to add two complex numbers like c3=c1+c2 where c1,c2 and c3 are complex numbers.The complete source in C++ to implement operator overloading is provided below

 #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();  
 }