C++ Online Quiz

Following quiz provides Multiple Choice Questions (MCQs) related to C++ Framework. You will have to read all the given answers and click over the correct answer. If you are not sure about the answer then you can check the answer using Show Answer button. You can use Next Quiz button to check new set of questions in the quiz.

Questions and Answers

Q 1 - A trigraph character begins with

A - #

B - ##

C - ?

D - ??

Answer : C

Explaination

Few characters have alternative representation and start with ??. Eg. Fro [ equivalent is ??(

Q 2 - Which data type can be used to hold a wide character in C++?

A - unsigned char;

B - int

C - wchar_t

D - none of the above.

Answer : C

Explaination

wchar_t is the data type using which we can hold Unicode characters.

Answer : B

Explaination

Only members of the derived class and the same class can access a protected member.

Q 4 - What is the output of the following program?

#include<iostream>

using namespace std;
class Base {
public: 
   virtual void f() { 
      cout<<"Base\n";
   }
};

class Derived:public Base {
public: 
   void f() { 
      cout<<"Derived\n";
   }
};

main() { 
   Base *p = new Derived();
   p->f();

}

A - Base

B - Derived

C - Compile error

D - None of the above.

Answer : B

Explaination

The overridden method f() of the created object for derived class gets called.

#include<iostream>

using namespace std;
class Base {
public: 
   virtual void f() { 
      cout<<"Base\n";
   }
};

class Derived:public Base {
public: 
   void f() { 
      cout<<"Derived\n";
   }
};

main() { 
   Base *p = new Derived();
   p->f();

}

Q 5 - What is the output of the following program?

#include<iostream>

using namespace std;
main() { 
   int *p = new int; 
   delete p; 
   delete p; 
   cout<<"Done";
}

A - Done

B - Compile error

C - Runtime error

D - None of the above

Answer : C

Explaination

It is invalid to release memory more than once.

#include<iostream>

using namespace std;
main() { 
   int *p = new int; 
   delete p; 
   delete p; 
   cout<<"Done";
}

Answer : C

Explaination

A constructor cant be overridden.

Q 7 - What is the output of the following program?

#include<iostream>

using namespace std;
void f() {
   cout<<"Hello"<<endl;
}
main() {
}

A - No output

B - Error, as the function is not called.

C - Error, as the function is defined without its declaration

D - Error, as the main() function is left empty

Answer : A

Explaination

No output, apart from the option (a) rest of the comments against the options are invalid

#include<iostream>

using namespace std;
void f() {
	cout<<"Hello"<<endl;
}
main() 
{
}

Q 8 - What is the output of the following program?

#include<iostream>

using namespace std;
main() { 
   int r, x = 2;
   
   float y = 5;
  
   r = y%x;
   cout<<r; 
}

A - 1

B - 0

C - 2

D - Compile error

Answer : D

Explaination

Answer Compile Error, It is invalid that either of the operands for the modulus operator (%) is a real number.

#include<iostream>

using namespace std;
main() { 
   int r, x = 2;
   
   float y = 5;
  
   r = y%x;
   cout<<r; 
}

Q 9 - What is the output of the following program?

#include<iostream>

using namespace std;
int x = 5;

int &f() {
	return x;
}
main() {
	f() = 10;
   cout<<x;
}

A - 5

B - Address of x

C - Compile error

D - 10

Answer : D

Explaination

A function can return reference, hence it can appear on the left hand side of the assignment operator.

#include<iostream>

using namespace std;
int x = 5;

int &f() {
	return x;
}
main() {
	f() = 10;
   cout<<x;
}

Q 10 - Does both the loops in the following programs prints the correct string length?

#include<iostream>

using namespace std;
main() {
   int i;
   
   char s[] = "hello";

   for(i=0; s[i]; ++i);
      cout<<i<<endl;

   i=0; 
   
   while(s[i++]);
      cout<<i;
}

A - Yes, both the loops prints the correct length

B - Only for loop prints the correct length

C - Only while loop prints the correct length

D - Compile error in the program.

Answer : B

Explaination

In while loop 'i' gets incremented after checking for '\0', hence giving 1 more than the length.

#include<iostream>

using namespace std;
main() {
   int i;
   
   char s[] = "hello";

   for(i=0; s[i]; ++i);
      cout<<i<<endl;

   i=0;
   
   while(s[i++]);
      cout<<i;
}
cpp_questions_answers.htm
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