Tutorials
Courses
Tracks

Constructors, Destructors, and this Pointer

Last Updated :

Discuss

Comments

Question 1

When a copy constructor may be called?

When an object of the class is returned by value.
When an object of the class is passed (to a function) by value as an argument.
When an object is constructed based on another object of the same class
When compiler generates a temporary object.
All of the above

Discuss it

Question 2

Predict the output of the following program?

C++

#include <iostream>
using namespace std;

class GfG {
    GfG() {
        cout << "Constructor Called" << endl;
    }
};

int main() {
    cout << "Main Started" << endl;
    return 0;
}

Compiler Error
Main Started
Constructor Called
Constructor Called
Main Started
Main Started

Discuss it

Question 3

Can destructors be private in C++?

Discuss it

Question 4

What is the use of this pointer?

When local variable’s name is same as member’s name, we can access member using this pointer.
To return reference to the calling object
Can be used for chained function calls on an object
All of the above

Discuss it

Question 5

Predict the output of following C++ program

CPP

#include<iostream>
using namespace std;

class Test
{
private:
  int x;
  int y;
public:
  Test(int x = 0, int y = 0) { this->x = x; this->y = y; }
  static void fun1() { cout << "Inside fun1()"; }
  static void fun2() { cout << "Inside fun2()"; this->fun1(); }
};

int main()
{
  Test obj;
  obj.fun2();
  return 0;
}

Inside fun2() Inside fun1()
Inside fun2()
Inside fun1() Inside fun2()
Compiler Error

Discuss it

Question 6

Predict the output of following C++ program?

CPP

#include<iostream>
using namespace std;

class Test
{
private:
  int x;
public:
  Test() {x = 0;}
  void destroy()  { delete this; }
  void print() { cout << "x = " << x; }
};

int main()
{
  Test obj;
  obj.destroy();
  obj.print();
  return 0;
}

x = 0
undefined behavior
compiler error
runtime error

Discuss it

Question 7

What is the purpose of a default constructor in C++?

To create an object with default values
To create an object with specific initial values
To create a copy of an existing object
To transfer resources from a temporary object

Discuss it

Question 8

What will be the output?

C++

#include <iostream>
class Test {
public:
    ~Test() {
        std::cout << "Destructor called\n";
    }
};

int main() {
    Test t1;
}

No output
Destructor called
Compilation error
Runtime Error

Discuss it

Question 9

What will be the output?

C++

#include <iostream>
class Sample {
public:
    ~Sample() {
        std::cout << "Destructor executed\n";
    }
};

void createObject() {
    Sample s;
}

int main() {
    createObject();
    std::cout << "Main done\n";
}

Main done
Destructor executed
Destructor executed
Main done
Main done
Destructor executed

Discuss it

Tags:

C++

There are 9 questions to complete.

Take a part in the ongoing discussion