C++ Multiple Choice Questions Page 14 of 14

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Question: 261

#include<iostream>
using namespace std;

class cppbuzz_base{
    public: 
    
    void hello(){
        cout<<"Hello Base ";
    }
};

class derived: public cppbuzz_base{
    public:
    
    void hello(){
        cout<<"Hello Derived ";
    }
    
};

int main()
{
cppbuzz_base baseObj;
derived obj = derived(baseObj);
obj.hello();
return 0;
}

(A) Hello Derived
(B) Hello Base
(C) Hello Derived Hello Base
(D) Error: not matching func to call ‘derived::derived(cppbuzz_base&)’

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Level: Practitioner

Category of MCQ: typecasting in C++

Question: 262

//find the output of below code on Singleton class

#include <iostream>

class Singleton
{
    private:
        static Singleton* instance;
        Singleton();

    public:
        static Singleton* getInstance();
};

Singleton* Singleton::instance = 0;

Singleton* Singleton::getInstance()
{
    if (instance == 0)
    {
        instance = new Singleton();
    }

    return instance;
}

Singleton::Singleton()
{}

int main()
{
    Singleton* one = Singleton::getInstance(); 
    Singleton* two = Singleton::getInstance();

    if(one == two)
    std::cout<<"Both pointers hold same object";
    else
    std::cout<<"They don't hold same object";
    
    return 0;
}

(A) Both pointers hold same object
(B) They don't hold same object
(C) Compilation Error
(D) Exception occured

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Level: Practitioner

Category of MCQ: singleton in C++

Question: 263

Note: Mandatory steps to follow while declaring Singleton class

1. Private Constructor
2. Private Copy Constructor : Not Implemented
3. Private Assignment Operator: Not Implemented

(A)
(B)
(C)
(D)

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Level: Practitioner

Category of MCQ: singleton in C++

Question: 264

#include<iostream>

class cppbuzz{
    
  public:
        cppbuzz(){
            std::cout<<"cppbuzz";
        }
        ~cppbuzz(){
            std::cout<<"~cppbuzz";
        }
        
        virtual void myfunc() = 0;
};

int main(){
    cppbuzz obj;
    return 0;
}

(A) error: cannot declare variable ‘obj’ to be of abstract type ‘cppbuzz’
(B) cppbuzz
(C) ~cppbuzz
(D) cppbuzz~cppbuzz

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Level: Practitioner

Category of MCQ: abstract_class in C++

Question: 265

//if the size of a is 4 bytes then find the output of below code 

#include<iostream>

class cppbuzz{
    private: int a;
    public: virtual void myfunc()=0;
};

int main(){
    std::cout<<sizeof(cppbuzz);
    return 0;
}

(A) 4
(B) 8
(C) 12
(D) 16

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Level: Expert

Category of MCQ: abstract_class in C++

Question: 266

Virtual base classes are used in virtual inheritance in a way of preventing multiple “instances” of a given class appearing in an inheritance hierarchy when using multiple inheritances. (True of False)

(A) True
(B) False

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Level: Practionar

Category of MCQ: virtual_func in C++

Question: 267

#include<iostream>
using namespace std;

class Test
{
private: int x, y;
public:
        Test():y(10),x(y+10)
        {
        }
        
       void print()
       {
          cout<<x<<", "<<y;
       } 
};

int main()
{
Test *a = new Test();
a->print();

delete a;

return 0;
}

(A) Compilation Error
(B) 10, 20
(C) 10, 10
(D) 10, Undfefined Value

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Level: Expert

Category of MCQ: classesAndobjects in C++

Question: 268

What is the time complexity of the following C++ code? 

int sum;
int i = 0;
int j = N; 

while (i <= j) { 
   sum = sum + i;
   i++;
}

(A) O(log N)
(B) O(N/2)
(C) O(N)
(D) O(N^2)

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Level: Beginner