C++ Online Quiz


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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

Answer : D

Explaination

C++ supports all the forms of inheritance.

Q 2 - Choose the respective delete operator usage for the expression ‘ptr=new int[100]’.

A - delete ptr;

B - delete ptr[];

C - delete[] ptr;

D - []delete ptr;

Answer : C

Explaination

Q 3 - Pick up the valid declaration for overloading ++ in postfix form where T is the class name.

A - T operator++();

B - T operator++(int);

C - T& operator++();

D - T& operator++(int);

Answer : B

Explaination

The parameter int is just to signify that it is the postfix form overloaded. Shouldn’t return reference as per its original behavior.

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

#include<iostream>

using namespace std;
class Base {
public:
   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 : A

Explaination

The method f() is not overridden therefore as per the pointer type respective method is called.

#include<iostream>

using namespace std;
class Base {
public:
   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";
}

Q 6 - (i) ‘ios’ is the base class of ‘istream’

(ii) All the files are classified into only 2 types. (1) Text Files (2) Binary Files.

A - Only (i) is true

B - Only (ii) is true

C - Both (i) & (ii) are true

D - Both (i) & (ii) are false

Answer : C

Explaination

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

#include<iostream>

using namespace std;
main() {
   enum { 
      india, is = 7, GREAT 
   };

   cout<<india<<" "<<GREAT;
}

A - 0 1

B - 0 2

C - 0 8

D - Compile error

Answer : C

Explaination

0 8, enums gives the sequence starting with 0. If assigned with a value the sequence continues from the assigned value.

#include<iostream>

using namespace std;
main() {
   enum { 
      india, is = 7, GREAT 
   };

   cout<<india<<" "<<GREAT;
}

Q 8 - What will be the output of the following program?

#include<iostream>
#include<string.h>

using namespace std;
main() {
   cout<<strcmp("strcmp()","strcmp()");
}

A - 0

B - 1

C - -1

D - Invalid use of strcmp() function

Answer : A

Explaination

0, strcmp return 0 if both the strings are equal

#include<iostream>
#include<string.h>

using namespace std;
main() {
   cout<<strcmp("strcmp()","strcmp()");
}

Q 9 - Identify the C++ compiler of Linux

A - cpp

B - g++

C - Borland

D - vc++

Answer : B

Explaination

g++ is GNU C++ compiler for linux. Borland and vc++ (Microsoft visual c++) for windows.

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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