C++ Online Test

1. By default, all the files in C++ are opened in _________ mode.

2. What will be the output of the following C++ code?

    #include <iostream>
    using namespace std;
    class BaseClass 
    {
        protected:
        int i;
        public:
        BaseClass(int x) 
        {
            i = x;
        }
        ~BaseClass() 
        {
        }
    };
    class DerivedClass: public BaseClass 
    {
        int j;
        public:
        DerivedClass(int x, int y): BaseClass(y)
        {
            j = x;
        }
        ~DerivedClass() 
        {
        }
        void show() 
        {
            cout << i << " " << j << endl;
        }
    };
    int main()
    {
        DerivedClass ob(3, 4);
        ob.show();
        return 0;
    }

3. Why do we need to handle exceptions?

4. What will be the output of the following C++ code in a 32-bit machine?

    #include <iostream>
    using namespace std;
    int main()
    {
        int num = 0x20 + 020 + 20;
        cout << sizeof(num)<<'\n';
        return 0;
    } 

5. What will be the output of the following C++ code?

    #include <iostream>
    #include <string>
    #include <algorithm>
    using namespace std;
    int main() 
    {
        string s = "spaces in text";
        s.erase(remove(s.begin(), s.end(), ' ' ), s.end() ) ;
        cout << s << endl;
    }

6. Which of the following is correct about none() function in bitset?

7. What happens if the following C++ program is compiled?

#include <iostream>
#include <string>
using namespace std;
class A
{
	int a;
   public: 
	A(){
		a = 0;
	}
	void show(){
		a++;
		cout<<"a: "<<a<<endl;
	}
};

class B: private A
{
   public:
	void show(){
		show();
	}
};

int main(int argc, char const *argv[])
{
	B b;
	b.show();
	return 0;
}

8. What will be the output of the following C++ code?

  
    #include <iostream>
    using namespace std;
    int main ()
    {
        int n;
        n = -77;
        cout.width(4); 
        cout << internal << n << endl;
        return 0;
    }

9. Which of the following is the default return value of functions in C++?

10. Which keyword is used to declare the min and max functions?

11. What are the essential operators in c++?

12. Is the size of character literals different in C and C++?

13. What will be the output of the following C++ code?

  
    #include <iostream>
    #include <exception>
    using namespace std;
    void myunexpected ()
    {
        cout << "unexpected called\n";
        throw 0;
    }
    void myfunction () throw (int) 
    {
        throw 'x';
    }
    int main () 
    {
        set_unexpected (myunexpected);
        try 
        {
            myfunction();
        }
        catch (int) 
        {
            cout << "caught int\n";
        }
        catch (...)  
        { 
            cout << "caught other exception\n"; 
        }
        return 0;
    }

14. Which of the following is correct?

15. Which value is pointed out first in heap?

16. What will be the output of the following C++ code?

    #include <iostream>
    #include <vector>
    using namespace std;
    int main ()
    {
        vector<bool> mask;
        mask.push_back(true);
        mask.flip();
        cout << boolalpha;
        for (unsigned i = 0; i < mask.size(); i++)
        cout << mask.at(i);
        return 0;
    }

17. Which operators are used in the free store?

18. What is the order of Destructors call when the object of derived class B is declared, provided class B is derived from class A?

19. Which word is used to stop the unpacking of a value in a tuple?

20. What will be the output of the following C++ code?

    #include <iostream>
    using namespace std;
    int main()
    {
        char *ptr;
        char Str[] = "abcdefg";
        ptr = Str;
        ptr += 5;
        cout << ptr;
        return 0;
    } 

21. What will be the output of the following C++ code?

 
    #include <iostream>
    using namespace std;
    class class0 
    {
        public:
        virtual ~class0(){}
        protected:
        char p;
        public:
        char getChar();
    };
    class class1 : public class0 
    {
        public:
        void printChar();
    };
    void class1::printChar()
    {
        cout  << "True" << endl;
    }
    int main() 
    {
        class1 c;
        c.printChar();
        return 1;
    } 

22. In which type of semantics does c++ implements iterator?

23. Pick the correct statement.

24. Which is present in the basic interface of the allocator interface?

25. What type of access does deque and vector provide?

26. What will be the output of the following C++ code?

#include <iostream>
#include <valarray>
using namespace std;
int main()
{
    valarray<int> varr = { 10, 2, 20, 1, 30 };
    for (int &x: varr) cout << x << " ";
    cout<<endl;
    varr = varr.apply([](int x){return x+=5;});
    for (int &x: varr) cout << x << " ";
    return 0;
}

27. What will be the output of the following C++ code?

  
    #include <iostream>
    #include <string>
    using namespace std;
    int main ()
    {
        string str ("Steve jobs");
        cout << str.capacity() << "\n";
        return 0;
    }

28. Pick out the correct statement about multiple inheritances.

29. Pick the incorrect statement about inline functions in C++?

30. What will be the output of the following C++ code?

    #include <iostream>
    using namespace std;
    int main()
    {
        int num1 = 10;
        float num2 = 20;
        cout << sizeof(num1 + num2);
        return 0;
    } 

31. What are the advantages of passing arguments by reference?

32. Pick out the correct statement.

33. In which part of the for loop termination condition is checked?
for(I;II;III)
{IV}

34. How many ways of passing a parameter are there in c++?

35. What will be the output of the following C++ code?

#include <stdio.h>
int main()
{
   const int x;
   x = 10;
   printf("%d", x);
   return 0;
}

36. In case of non-static member functions how many maximum object arguments a binary operator overloaded function can take?

37. Suppose in a hypothetical machine, the size of char is 32 bits. What would sizeof(char) return?

38. Which container is used to store elements as key-value pair?

39. What is a copy constructor?

40. What will be the output of the following C++ code?

  
    #include <iostream>
    #include <set>
    using namespace std;
    int main()
    {
        set<int> tst;
        tst.insert(12);
        tst.insert(21);
        tst.insert(32);
        tst.insert(31);
        set<int> :: const_iterator pos;
        for(pos = tst.begin(); pos != tst.end(); ++pos)
        cout << *pos << ' ';
        return 0;
    }

41. What will be the output of the following C++ code?

#include <iostream>
using namespace std;
template <class T>
class Test
{
  private:
    T val;
  public:
    static int count;
    Test()  {   
    	count++;   
    }
};
template<class T>
int Test<T>::count = 0;
int main()
{
    Test<int> a;
    Test<int> b;
    Test<double> c;
    cout << Test<int>::count << endl;
    cout << Test<double>::count << endl;
    return 0;
}

42. What is the use of no linkage?

43. Which of the following statements is NOT valid about operator overloading?

44. Which constructor will initialize the base class data member?

45. Identify the incorrect option.

46. What will be the output of the following C++ code?

    #include <iostream>
    using namespace std;
    class base
    {
        int val1, val2;
        public:
        int get()
	{
            val1 = 100;
            val2 = 300;
	}
        friend float mean(base ob);
    };
    float mean(base ob)
    {
        return float(ob.val1 + ob.val2) / 2;
    }
    int main()
    {
        base obj;
        obj.get();
        cout << mean(obj);
        return 0;
    }

47. Which of the following is correct about bitset and vector of bools?

48. What will be the output of the following C++ code?

    #include <iostream>
    using namespace std;
    void PrintSequence(int StopNum)
    {
        int Num;
        Num = 1;
        while (true)
        {
            if (Num >= StopNum)
                throw Num;
            cout << Num << endl;
            Num++;
        }
    }
    int main(void)
    {
        try
        {
            PrintSequence(2);
        }
        catch(int ExNum)
        {
            cout << "exception: " << ExNum << endl;
        }
        return 0;
    }

49. What will the monetary facet will do?

50. Which of the following function is used to initialize a tuple?