C++ LANGUAGE UNARY OPERATORS OVERLOADING

COMPUTER LANGUAGES HTML,C,C++.JAVA,.NET AND MULTIMEDIA basics and programs click home button

C++ LANGUAGE UNARY OPERATORS OVERLOADING

Unary Operators Overloading 


The unary operators operate on a single operand and 
following are the examples of Unary operators: 


• The increment (++) and decrement (--) operators. 

• The unary minus (-) operator. 



• The logical not (!) operator. 

The unary operators operate on the object for which they were 
called and normally, this operator appears on the left side of 
the object, as in !obj, -obj, and ++obj but sometime they can 
be used as postfix as well like obj++ or obj--. 
Following example explain how minus (-) operator can be 
overloaded for prefix as well as postfix usage. 

#include <iostream> 
using namespace std; 
  
class Distance 
{ 
   private: 
      int feet;             // 0 to infinite 
      int inches;           // 0 to 12 
   public: 
      // required constructors 
      Distance(){ 
         feet = 0; 
         inches = 0; 
      } 
      Distance(int f, int i){ 
         feet = f; 
         inches = i; 
      } 
      // method to display distance 
      void displayDistance() 
      { 
         cout << "F: " << feet << " I:" << inches <<endl; 
      } 
      // overloaded minus (-) operator 
      Distance operator- ()   
      { 
         feet = -feet; 
         inches = -inches; 
         return Distance(feet, inches); 
      } 
}; 
int main() 
{ 
   Distance D1(11, 10), D2(-5, 11); 
  
   -D1;                     // apply negation 
   D1.displayDistance();    // display D1 
 
   -D2;                     // apply negation 
   D2.displayDistance();    // display D2 
 
   return 0; 
} 

When the above code is compiled and executed, it produces the following result: 

F: -11 I:-10 
F: 5 I:-11 
Hope above example makes your concept clear and you can 
apply similar concept to overload Logical Not Operators (!).