C++ Programming - OOPS Concepts - Discussion

Here is an example you can understand clearly :).

#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;
}

Constructor having same class name that's why we are call the constructor at the time of object creation.

Object creation is:.

Classname refernce variable=new classname () ;.

In this constructor name n classname is also same that's why we are call the constructor at the time of object creation.

While creating an object, memory is allocated to that object when its constructor is invoked, it invokes only once during declaration of object, if you have not defined any constructor inside class then default constructor is invoked.

constructor is called at the time of object creation.

#include<iostream>
using namespace std;
class A
{
public:
A()
{
cout<<"constructor"<<endl;
}
}
int main()
{
A b1;
}

A constructor is called at the time of declaration of an object.

class A {};
class C /* declaration of a class */
{
A a_; /* declaration of an object (but not definition) of type A */
};

will call the constructor of A?

Constructor is call when an object is created or initialize. When we not write a code for constructor then compiler automatically added default constructor.

The constructor is a special member function of a class which is called/invoked when the object is created. It has the same name as that of a class.

Constructor is a special member function of a class which is called/invoked when the object is created. It has the same name as that of a class.

A constructor is called whenever an object is created and declaration is nothing but creation of an object.

A constructor is always called when an object is initialized, not declared and certainly not "used".