C++ LANGUAGE CONSTRUCTOR AND DESTRUCTOR

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C++ LANGUAGE CONSTRUCTOR AND DESTRUCTOR

Constructor & Destructor 


A class constructor is a special member function of a class 
that is executed whenever we create new objects of that class. 
A constructor will have exact same name as the class and it 
does not have any return type at all, not even void. 
Constructors can be very useful for setting initial values 
for certain member variables. 


Following example explains the concept of constructor:

 
#include <iostream> 
  
using namespace std; 
  
class Line 
{ 
   public: 
      void setLength( double len ); 
      double getLength( void ); 
      Line();  // This is the constructor 
  
   private: 
      double length; 
}; 
  
// Member functions definitions including constructor 
Line::Line(void) 
{ 
    cout << "Object is being created" << 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