C++ Design Patterns
C++ Creational Design Patterns

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.

Q 1 - What is the output of the following program?

#include<iostream>

using namespace std;
class abc { 
   public: 
      static int x; 
      int i; 

      abc() {
         i = ++x;
      }
   };
int abc::x;

main() { 
   abc m, n, p;
   
   cout<<m.x<<" "<<m.i<<endl;
}

Answer : A

Explaination

The static member variable x shares common memory among all the objects created for the class.

#include<iostream>

using namespace std;
class abc { 
   public: 
      static int x; 
      int i; 

      abc() {
         i = ++x;
      }
   };
int abc::x;

main() { 
   abc m, n, p;
   
   cout<<m.x<<" "<<m.i<<endl;
}

Q 2 - From the below class choose the proper definition of the member function f().

template <class T>

class abc {
   void f();
};

A - template <class T>

void abc<T>::f() { }

B - template<class T>

void abc::f() { }

C - template<T>

void abc<class T>::f() { }

D - template<T>

void abc<T>::f() { }

Answer : A

Explaination

Q 3 - Operators sizeof and ?:

A - Both can be overloaded

B - Both cannot be overloaded

C - Only sizeof can be overloaded

D - Only ?: can be overloaded

Answer : B

Explaination

Both the mentioned operators cannot be overloaded.

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

A - Base

B - Derived

C - Compile error

D - None of the above.

Answer : A

Explaination

The method f() inherited from Base is referred using :: operator.

#include<iostream>

using namespace std;
class Base {
public:
   void f() {
      cout<<"Base\n";
   }
};
class Derived:public Base {
public:
   void f() {
      cout<<"Derived\n";
   }
};
main() { 
   Derived obj; 
   obj.Base::f();
}

Q 6 - Choose the option not applicable for the constructor.

A - Cannot be called explicitly.

B - Cannot be overloaded.

C - Cannot be overridden.

D - None of the above.

Answer : C

Explaination

A constructor cant be overridden.

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

#include<iostream>

using namespace std;
main() { 
   int x = 5;

   if(x==5) {	
      if(x==5) break;
      cout<<"Hello";
   } 

   cout<<Hi; 
}

Answer : A

Explaination

compile error, keyword break can appear only within loop/switch statement.

#include<iostream>

using namespace std;
main() { 
   int x = 5;

   if(x==5) {	
      if(x==5) break;
      cout<<"Hello";
   } 

   cout<<Hi; 
}

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

#include<iostream>

using namespace std;
main() { 
   float t = 2;
	
	switch(t) {
      case 2: cout<<Hi;
		default: cout<<"Hello";
	}
}

Answer : D

Explaination

Error, switch expression cant be float value

#include<iostream>

using namespace std;
main() { 
   float t = 2;
	
	switch(t) {
		case 2: cout<<Hi;
		default: cout<<"Hello";
	}
}

Q 9 - Choose the invalid identifier from the below

Answer : B

Explaination

bool is the reserved keyword and cannot be used an identifier name.

Q 10 - What is the built in library function to compare two strings?

Answer : B

Explaination

strcmp() is the built in function from string.h to compare two strings. Returns 0 if both are same strings. Returns -1 if first < second string. Returns 1 first > second.

cpp_questions_answers.htm