C++ LANGUAGE CLASS DESTRUCTOR

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C++ LANGUAGE CLASS DESTRUCTOR

The Class Destructor 


A destructor is a special member function of a class that is 
executed whenever an object of it's class goes out of scope or 
whenever the delete expression is applied to a pointer to the 
object of that class. 

A destructor will have exact same name as the class prefixed 
with a tilde (~) and it can neither return a value nor can it 
take any parameters. Destructor can be very useful for releasing 
resources before coming out of the program like closing files, 
releasing memories etc. 

Following example explains the concept of destructor: 

#include <iostream> 
  
using namespace std; 
  
class Line 
{ 
   public: 
      void setLength( double len ); 
      double getLength( void ); 
      Line();   // This is the constructor declaration 
      ~Line();  // This is the destructor: declaration 
  
   private: 
      double length; 
}; 
  
// Member functions definitions including constructor 
Line::Line(void) 
{ 
    cout << "Object is being created" << endl; 
} 
Line::~Line(void) 
{ 
    cout << "Object is being deleted" << endl; 
} 
  
void Line::setLength( double len ) 
{ 
    length = len; 
} 
  
double Line::getLength( void ) 
{ 
    return length; 
} 
// Main function for the program 
int main( ) 
{ 
   Line line; 
  
   // set line length 
   line.setLength(6.0);  
   cout << "Length of line : " << line.getLength() <<endl; 
  
   return 0; 
} 
 
 
 
When the above code is compiled and executed, 
it produces the following result: 


Object is being created 
Length of line : 6 
Object is being deleted