C++ Interview Questions and Answers


Describe PRIVATE, PROTECTED and PUBLIC – the differences and give examples.

class Point2D{

int x; int y;

public int color;

protected bool pinned;

public Point2D() : x(0) , y(0) {} //default (no argument) constructor


Point2D MyPoint;

You cannot directly access private data members when they are declared (implicitly)

MyPoint.x = 5; // Compiler will issue a compile ERROR

//Nor yoy can see them:

int x_dim = MyPoint.x; // Compiler will issue a compile ERROR

On the other hand, you can assign and read the public data members:

MyPoint.color = 255; // no problem

int col = MyPoint.color; // no problem

With protected data members you can read them but not write them: MyPoint.pinned
= true; // Compiler will issue a compile ERROR

bool isPinned = MyPoint.pinned; // no problem

Posted by:Richards