What is constructor? How user can declared constructor in derived class? Explain with example.

What is constructor? How user can declared constructor in derived class? Explain with example.
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1 Answer

Answer :

Constructor:- Constructor is a special member function which has same name as a class name and is used to initialize object during compile time of program.

Declaring constructor in derived class If a base class contains a constructor with one or more arguments then it is mandatory for the derived class to have a constructor and pass the argument to the base class constructor. A header line of derived constructor function contains two parts separated by a colon (:) First part provides the declaration of the arguments that are passed to the derived constructor and the second part lists the function calls to the base constructors.

image

Example:

#include<iostream.h>

#include<conio.h>

class base

{

int a;

public:

base(int x)

{

a=x;

}

void displaybase()

{

cout<<a;

}

};

class derived:public base

{

int b;

public:

derived (int x,int y):base(x)

{

b=y

}


void display()
{
cout<<b;
}
};
void main()
{
derived d(2,5);
d.displaybase();
d.display();
getch();
}
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