Parameterized constructor

Parameterized Constructor:

A default constructor does not have any parameter, but if you need, a constructor can have parameters. This helps you to assign initial value to an object at the time of its creation as shown in the following example:

#include <iostream>
 
using namespace std;
 
class Line
{
   public:
      void setLength( double len );
      double getLength( void );
      Line(double len);  // This is the constructor
 
   private:
      double length;
};
 
// Member functions definitions including constructor
Line::Line( double len)
{
    cout << "Object is being created, length = " << len << endl;
    length = len;
}
 
void Line::setLength( double len )
{
    length = len;
}
 
double Line::getLength( void )
{
    return length;
}
// Main function for the program
int main( )
{
   Line line(10.0);
 
   // get initially set length.
   cout << "Length of line : " << line.getLength() <<endl;
   // set line length again
   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 = 10
Length of line : 10
Length of line : 6