CPP MCQS AND PROBLEM STATEMENTS
Select True or False:
1. Data items in a class may be public.
2. Class members are public by default.
3. Friend functions have access only to public members of the class.
4. A function designed as public can be accessible by non-members of a class.
5. Friendship is commutative.
6. new and delete are operators.
7. We can implement generic classes using templates
8. Using operator overloading we can invent new operators
9. Inheritance helps in making a general class into a more specific class.)
10. Classes can be inherited privately.
11. Constructors can be virtual like virtual destructors
12. A class encapsulates the implementation and interface of a user-defined data type and constitutes an abstract data type.
13. std::cout is a standard input stream.
14. Preprocessor #define macro and inline functions use the same mechanism.
15. The new operator returns the address and size of the memory block that it allocates.
16. The heap storage is used for local objects.
17. There can be a null reference.
18. One can change the value of a reference after it is initialized.
19. It is nothing wrong that a function returning a reference to an automatic variable.
20. The preprocessor processes source code before the compiler does.
21. A function template defines a parameterized nonmember function, which enables a program to call the same function with different types of arguments.
22. Destructors can be overloaded.
23. Static data members cannot be private.
24. Static member functions can use this pointer.
25. One cannot use enumerations in a class.
26. One cannot create an object of a virtual class.
27. The push operation inserts an element at the end of a stack.
28. It is not possible to rethrow an exception.
29. There can be only one catch block in a program.
30. When an exception if throw, but not caught, the program ignorers the error.
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1) Why would your class have a pure virtual function?
1) To insure that this function is overridden in derived classes that are to be instantiated.
2) To allow for templated classes to be used with friend functions.
3) To maximize the execution speed of the function providing that memory is not at a premium.
4) To maximize the memory efficiency providing that execution speed is not at a premium.
2) In most cases, a benefit of inheritance is that it ________.
1) eliminates redundant classes
2) increases program execution speed
3) enhances security
4) reduces work
3) Reusable and extensible are feature of
1) Abstraction
2) Encapsulation
3) Polymorphism
4) Inheritance
4) In order for function f to use a private attribute belonging to class C, you must___.
1) declare f a friend in C
2) declare C a friend in f
3) Both of the above
4)None of above
5) Function can be overloaded.
1) When they have same name and return type.
2) When they have same name and return type and diff parameters.
3) When they have same name and diff return type and diff parameter.
4)When they have same name and diff type of parameters or diff no of parameters, return type does not matter.
6) Classes are useful because they
a) encapsulate all the features of an entity in one place
b) can be consider similar to real existing objects
c) provide direct access to information
d) bring together all aspects of and entity in one place
1) a and b 2) a, b and c 3) a, b and d 4) a to d
7) With inheritance new capabilities are added to
a) The base class b) Both the base and the derived class c) the derived class d) none of the above
8) What is the main purpose of creating a abstract base class
a) Creating dynamic objects b) Dynamic binding c) Deriving classes d) none of these
9) If a class D is derived from A and B is derived from class D then it is called as ______ inheritance
a) Multiple b) Hierarchical c) Multilevel d) Single
10) static member functions
a. can access only static members in the same class
b. can access non-static members
c. can access constant members
d. both (a) and (c) above
11) (i) constructors can be virtual
(ii) destructors can’t be virtual
which of the above statements are true
a. both are true b. both are false
c. (i) is true & (ii) is false d. (ii) is true & (i) is false
12. Which one of the following is pure virtual function
a. virtual void funct (int n) b. virtual void funct ( ) {}
c. virtual funct (int n); d. virtual void funct (int n) = 0;
13. virtual function can be defined in …………… section of a class
a. private b. public c. protected d. anywhere
14. A variable defined within a block is visible
a. throughout the function
b. from the point of definition onward in the block
c. from the point of definition onward in the function
d. from the point of definition onward in the program
15. Which one of the following is true statement?
a. friend function can access public data only
b. scope of friend function is limited within the class where it is declared
c. a friend function can’t be called using the object of that class
d. if friend is declared in private, it works differently when declared in public.
16. Argument of a copy constructor is passed by
a. value b. reference c. address d. none of the above
17. Inline member function is treated like
a. macro b. normal function c. preprocessor d. member function
18. Choose the correct answer
Statement (i). C++ allows all operators to be overloaded
Statement (ii) Friend function can’t be used with binary operator
Statement (iii) Friend function can access private member of a class
Statement (iv) In binary operator overloading left hand operand is used to invoke the operator function and the
right-hand operand as an argument to the operator function.
a. Statement (i) (iii) & (iv) are correct c. statement (iii) & (iv) are correct
b. all are correct d. statement (i) (ii) (iii) are correct
19. The new operator in C++
a. creates a variable called new b. obtains memory for a new variable
c. returns a pointer to a variable d. all of the above
e. both (b) and (c) above
20. How many values can be returned from a function?
a. 1 b. 2 c. 4 d. any number
21. In C++, when an argument is passed by reference
a. the function cannot access the argument’s value
b. a temporary variable is created in the calling program to hold the arguments value
c. a variable is created in the function to hold the arguments value
d. the function accesses the arguments original value in the calling program
22. In general in C++, the dot operator (or class member access operator) connects the following two entities
a. a class and a member of that class
b. a class object and a class
c. a class member and a class object
d. a class object and a member of that class
23.In object orient programming classes are useful because they
a. can closely model objects in the real world
b. bring together all aspects of an entity in one place
c. permit data to be hidden from other classes
d. all of the above
24. In C++, a pure virtual function is a virtual function that
a. has no body b. is used in a base class c. returns nothing
d. both (a) and (b) above e. all (a), (b), (c) above
25. In C++, when an array name is passed to a function, the function
a. access exactly the same array as the calling program
b. refers to the same array using a different name from that used by the calling program
c. all of the above
d. none of the above
26. In C++, a virtual base class is useful when
a. it makes to use a base class with no body
b. there are multiple paths from one derived class to another
c. different functions in base and derived classes have the same name
d. the identification of a function in a base class is ambiguous
27. Operator overloading is
a. making C++ operators work with objects
b. giving new meanings to existing C++ operators
c. making new C++ operators
d. both (a)and (b) above
28. In C++ language, the scope-resolution operator usually
a. specifics a particular class and resolves ambiguities
b. tells what base class is derived from
c. all of the above
29. A class hierarchy (in C++),
a. describes “has a” relarionships
b. describes “is a kind of” relationship
c. shows the same relationships as a family tree
d. show the same relationships as a organization chart
30. To delete a dynamically allocated array named ‘a’, the correct statement is
(a) delete a; (b) delete a[0]; (c) delete []a; (d) delete [0]a;
31. Which of the following statement is false about pointers?
(a) The ++ and -- operators may be used with pointer variables
(b) An integer may be added and subtracted from a pointer variable (c) A pointer may be added to another pointer.
(d) A pointer may be subtracted from another pointer.
31. A null pointer is a pointer that contains
(a) the address 0 (b) the address that points to 0
(c) the address that pointsto ‘\0’ (d) the address that points to -1
32. The design of classes in a way that hides the details of implementation from the user is known as:
(a) Encapsulation (b) Information Hiding
(c) Data abstraction (d) All of the above
33. I want a nonmember function to have access to the private members of a class. The class must declare that function:
(a) friend (b) inline
(c) static (d) virtual
34. A class member that is to be shared among all objects of a class is called
(a) A const member (b) A reference parameter
(c) A static member (d) A function member
35. A variable that is declared protected:
(a) Is visible only in the subclasses (and not in the class it is declared in).
(b) Is visible only in the class it is declared in.
(c) Is visible to all classes, but modifiable only in the class where it is declared. (d) Is visible in the class it is declared in, and all of its subclasses.
36. What is a destructor?
(a) A function called when an instance of a class is initialized.
(b)A function that is called when an instance of a class is deleted.
(c) A special function to change the value of dynamically allocated memory.
(d) A function that is called in order to change the value of a variable.
37. In protected inheritance:
(a) The public members of the base class become public. (b) The public members of the base class become protected.
(c) The protected members of the base class become private.
(d) The public members of the base class become inaccessible.
38. If a class declares a variable static, this means:
(a) Each instance of a class will have its own copy of the variable.
(b) Changing the variable in one instance will have no effect on other instances of the class. (c) There will be only one instance of the variable initialized for all classes.
(d) Every instance of the class must consider the value of the static variable before initializing.
39. In case of a copy constructor, which of the following is true?
(a) Used to instantiate an object from another existing object
(b) To copy one object to another existing object.
(c) Can be a substitute for a ‘=’ operator.
(d) All of the above.
40. Which of the following can be virtual?
(a) constructors (b) destructors
(c) static functions
(d) None of the above
41 Static memberfunctions
(a) can be used without an instantiation of an object.
(b) can only access static data. (c) Both 1 and 2 arecorrect.
(d) Neither 1 nor 2 are correct.
42. A performs the copying for value returns as well as for value parameters.
(a) Copy Constructor (b) Parameterize Constructor
(c) Default Constructor (d) none
43. What makes a class abstract?
(a) The class must not have method
(b) The class must have a constructor that takes no arguments (c) The class must have a function definition equal to zero
(d) The class may only exist during the planning phase
44)Which one of the following cannot be used with the virtual keyword?
a)Destructor
b)Member function
c)Constructor
d)None of the above
45)Which of the following is used for implementing the late binding?
a)Operator Functions
b)Virtual Functions
c)new Operator
d)Static Functions
46)Which of the following statement is not true about C++?
a)A class cannot have the data members as pointer.
b)Dynamic objects in c++ can be created only with the help of new operator.
c)Using abstract class we can achieve runtime polymorphism.
d)Static function can be overrided.
47)Which of the following statements is correct about the friend function in C++ programming language?
a)A friend function can access the private members of a class
b)A friend function is able to access protected members of a class
c)A friend function is able to access the public members of a class
d)All of the above
48)Which of the following can be considered as the correct syntax for declaring an array of pointers of integers that has a size of 10 in C++?
a)int *arr = new int*[10]
b)int *arr = new int[10];
c)int arr = new int[10];
d)int **arr = new int*[10];
49)Which one of the following statements correctly refers to the Delete and Delete[] in C++ programming language?
a)The "delete" is used for deleting the standard objects, while on the other hand, the "Delete[]" is used to delete the pointer objects
b)The "Delete" is a type of keyword, whereas the "Delete[]" is a type of identifier
c)The "Delete" is used for deleting a single standard object, whereas the "Delete[]" is used for deleting an array of the multiple objects
d)Delete is syntactically correct although, if the Delete[] is used, it will obtain an error
50)What will be the output of the following C++ code?
#include <iostream>
using namespace std;
int main ()
{
char str1[10] = "Hello";
char str2[10] = "World";
char str3[10];
int len ;
strcpy( str3, str1);
strcat( str1, str2);
len = strlen(str1);
cout<<len<<endl;
return 0;
}
a)5
b)12
c)10
d)11
51)Which one of the following given statements is not true about the references in C++?
a)Array of reference cannot be created.
b)A reference cannot refer to a constant value
c)A reference cannot be NULL
d)Once a reference is created, it cannot be later made to reference another object; it cannot be reset
52)Which of the following functions must use the reference in the argument list to avoid chain of calls?
a)Copy constructor
b)Virtual Function
c)Friend Function
d)Operator Function
53)Which of the following definition best describes the concept of polymorphism?
a)It is the ability to process the many messages and data in one way
b)It is the ability to process the undefined messages or data in at least one way
c)It is the ability to process the message or data in more than one form
d)It is the ability to process the message or data in only one form
54)Find the output of the following program.
int main()
{
char ch[] = "c++ programs";
int i = sizeof(ch);
cout << i << endl;
}
a)13
b)12
c)1
d)4
55)Which one of the following is the correct way to declare a pure virtual function?
a)virtual void Display(void){0};
b)virtual void Display = 0;
c)virtual void Display(void) = 0;
d)void Display(void) = 0;
56)Which of the following type of data member can be shared by all instances of its class?
a)Public
b)protected
c)Static
d)Friend
57)Which of the following type of class allows only one object of it to be created?
a)Virtual class
b)Abstract class
c)Singleton class
d)Friend class
58)Which of the following statement is correct?
a)Overloaded functions can accept same number of arguments.
b)Overloaded functions always return value of same data type.
c)Overloaded functions can accept only same number and same type of arguments.
d)Overloaded functions can accept only different number and different type of arguments.
59)Which of the following statement will be correct if the function has three arguments passed to it?
a)The trailing argument will be the default argument.
b)The first argument will be the default argument.
c)The middle argument will be the default argument.
d)All the argument will be the default argument.
60)What is the output of the Program?
class Base
{
int x, y;
public:
int z;
public:
Base()
{
x = y = z = 0;
}
void Display(void)
{
cout<< x << " " << y << " " << z << endl;
}
};
class Derived : public Base
{
int x, y;
public:
Derived(int xx = 65, int yy = 66)
{
y = xx;
x = yy;
}
void Display(void)
{
cout<< x << " " << y << " "<<z;
}
};
int main()
{
Derived objD;
objD.Display();
return 0;
}
a)000
b)66 65 0
c)66 65 garbage
d)none of the above.
61)What is the output of the Program?
#include <iostream>
using namespace std;
class Demo
{
int x, y;
public:
void SetValue(int &a, int &b)
{
a = 100;
x = a;
y = b;
Display();
}
void Display()
{
cout<< x << " " << y;
}
};
int main()
{
int x = 10;
Demo d;
d.SetValue(x, x);
return 0;
}
a)The program will print the output 100 10.
b)The program will print the output 100 100.
c)The program will print the output 100 garbage.
d)It will result in a compile time error.
62)What is the output of the Program?
#include <iostream>
using namespace std;
class Demo
{
public:
Demo(int xx)
{
cout<< xx;
}
~Demo()
{
cout<< "Final";
}
};
int main()
{
Demo *ptr = new Demo('B');
return 0;
}
a)Compile time error
b)B
c)garbage
d)66
63)What is the output of the program?
#include<iostream>
using namespace std;
class Base
{
public:
Base()
{
cout<< "Base OK. ";
}
~Base()
{
cout<< "Base OK. ";
}
};
class Derived: public Base
{
public:
Derived()
{
cout<< "Derived OK. ";
}
~Derived()
{
cout<< "Derived OK. ";
}
};
int main()
{
Derived b;
return 0;
}
a)Base OK. Derived OK.
b)Base OK. Base OK.Derived OK. Derived OK.
c)Base OK. Derived OK.Base OK. Derived OK.
d)Base OK. Derived OK. Derived OK. Base OK
64)
Assume that Honda is an instance of the Car class,
and that Car class has a member function named run.
Which of the following is a correct call to the run function?
a) Honda->run;
b) Honda.run();
c) run()
d) Honda()
65)#include <iostream>
using namespace std;
int main()
{
int array[] = {10, 20, 30};
cout << -2[array];
return 0;
}
a)-30
b)compiler error
c)garbage value
d)-15
66)Which of the following statement is correct about Virtual Inheritance?
a)It is a technique to ensure that a private member of a base class can be accessed
b)It is a technique to optimize the multiple inheritances
c)It is a technique to avoid the multiple inheritances of the classes
d)It is a C++ technique to avoid multiple copies of the base class into the derived or child classes
67)Which of the following offers a programmer the facility of using a specific class object into other classes?
a)Polymorphism
b)Abstraction
c)Inheritance
d)Composition
68)Among the following, which statement is correct about the Modularity?
a)Modularity means hiding the parts of the program
b)Modularity refers to dividing a program into subsequent small modules or independent parts
c)It refers to overloading the program's part
d)Modularity refers to wrapping the data and its functionality into a single entity
69. What is the output of the following code?
#include<iostream.h>
class professor{public:professor(){cout<<"professor ";};};
class researcher{public: researcher(){cout<<"researcher ";};};
class teacher: public professor{public: teacher(){cout<<"teacher ";};};
class myprofessor: public teacher, public virtual researcher
{public:myprofessor(){cout<<"myprofessor ";};};
int main()
{
myprofessor obj;
return 0;
}
(a) professor researcher teacher myprofessor
(b) researcher professor teacher myprofessor
(c) myprofessor teacher researcher professor
(d) myprofessor researcher professor teacher
70. What is the output of the following code?
#include<iostream.h>
class Parent
{
public:
Parent(){Status();}
virtual ~Parent() { Status();}
virtual void Status(){cout<<"Parent ";}
};
class Child: public Parent
{
public:
Child(){Status();}
virtual ~Child() { Status();}
virtual void Status(){cout<<"Child ";}
};
void main()
{
Child c;
}
(a) Parent Parent
(b) Parent Child Child Parent
(c) Child Parent Parent Child
(d) Error
71. What is the output of the following code?
#include<iostream.h>
int count=0;
class obj
{
public :
obj(){count++;}
~obj(){count--;}
};
int main()
{
obj A,B,C,D,E;
obj F;
{
obj G;
}
cout<<count;
return 0;
}
(a) 0
(b) 5
(c) 1 (d) 6
72. What is the output of the following code?
#include<iostream.h>
int main()
{
for(int ii=0;ii<3;++ii)
{
switch(ii)
{
case 0:cout<<"zero ";
case 1:cout<<"one ";continue;
case 2:cout<<"two ";break;
}
}
return 0;
}
(a) zero one one two b)error
(c) zero two
73. What is the output of the following code?
#include<iostream.h>
class obj
{
public :
obj(){cout<<"in ";}
~obj(){cout<<"out ";}
};
int main()
{
obj A,B;
{
obj D;
}
obj E;
return 0;
}
74. What is wrong in the following code?
#include<iostream.h>
class Base
{
public :
Base(){};
virtual ~Base(){};
};
class Derived : protected Base
{
public:
virtual ~Derived(){};
};
int main()
{
Base *pb = new Derived();
return 0;
(a) There is nothing wrong
(b) One cannot have a ‘Base’ pointer to ‘Derived’ since it is not derived publicly
(c) One need a derived class pointer to point to a derived class.
(d) One required to code a constructor for Derived.
75. What makes a class abstract?
(a) The class must not have method
(b) The class must have a constructor that takes no arguments
(c) The class must have a function definition equal to zero
(d) The class may only exist during the planning phase
76.
#include<iostream.h>
class Base
{
int static i;
public:
Base(){}
};
class Sub1: public virtual Base{};
class Sub2: public Base{};
class Multi: public Sub1, public Sub2 {};
void main()
{
Multi m;
}
In the above program, how many times Base’s constructor will be called?
(a) 1 (b) 2
(c) 3
(d) none
77.
#include<iostream.h>
namespace N1
{
int f(int n) {return n*2;}
}
namespace N2
{
int f(double n) {return n*3;}
}
void main()
{
using N1::f;
int i1=f(1.0);
using N2::f;
int i2=f(1.0);
}
In the above code what would be the values of i1 and i2
(a) i1=2 i2=2
(b) i1=2 i2=3
(c) i1=3 i2=2
78. What is the output of the following code?
#include<iostream.h>
int a = 1;
void main()
{
int a = 100;
{
int a = 200;
{
int a = 300;
cout<<a<<",";
}
cout<<a<<",";
}
cout<<a<<",";
cout<<::a<<",";
}
(a) Error
(b) 100, 200, 300, 100,
(c) 300, 200, 100, garbage,
(d) 300, 200, 100, 1,
79. What is the output of the following code?
#include<iostream.h>
void main()
{
int x=10;
(x<0)?(int a =100):(int a =1000);
cout<<a;
}
80. What is the output of the following code?
#include<iostream.h>
void main()
{
int a = 0;
cout<<(a = 10/a);
}
81. What is the output of the following code?
#include<iostream.h>
void main()
{
char str1[]=”India”, str2[]=”India”;
if(str1==str2)
cout<<”Both the string are same”;
else
cout<<”Both the string are not same”;
}
(a) Both the string are same
(c) Compile Time error
(b) Both the string are not same
(d) Runtime Error
===============================================================
FIND THE OUTPUT OF GIvEN PROGRAmS
82. What is the output of the following code if user enters “This is a test”?
#include<iostream.h>
#include<string.h>
void main()
{
char str[8];
cin>>str;
cout<<str;
}
83. What is the output of the following code?
#include<iostream.h>
void main()
{
int arr[] = {10,20,30,40,50};
int *ptr = arr;
cout<< *ptr++<<" "<<*ptr;
}
84
#include <iostream>
using namespace std;
int main()
{
char names[5][8] = {"rohan","geeta","rahul","rohit","rachana"};
for(int i=0;i<=5;i++)
{
cout << names[i] << endl;
cout<< *names[i]<<endl;
cout<<*(names+1)+0<<endl;
}
cout<<"---------------------------------------";
for(int i=0;i<=5;i++)
{
for(int j=0;j<=5;j++)
{
cout<< names[i][j];
}
cout<<endl;
}
cout<<"======================================="<<endl;
for(int i=0;i<=5;i++)
{
for(int j=0;j<=5;j++)
{
cout<<*(names+i)+j<<endl;
}
cout<<endl;
}
cout<<sizeof(names);
}
85)class A
{
public :
~A()
{
cout<<"In A's Destructor";
}
};
class B :public A
{
public :
~B()
{
cout<<"In B's Destructor";
}
};
int main()
{
A * aptr=new B();
delete aptr;
}
86
#include <iostream>
using namespace std;
// base class
class Base {
public:
virtual void function1()
{
cout << "Base function1()" << endl;
}
virtual void function2()
{
cout << "Base function2()" << endl;
}
virtual void function3()
{
cout << "Base function3()" << endl;
}
};
// class derived from Base
class Derived1 : public Base {
public:
// overriding function1()
void function1()
{
cout << "Derived1 function1()" << endl;
}
// not overriding function2() and function3()
};
// class derived from Derived1
class Derived2 : public Derived1 {
public:
// again overriding function2()
void function2()
{
cout << "Derived2 function2()" << endl;
}
// not overriding function1() and function3()
};
// driver code
int main()
{
// defining base class pointers
Base* ptr1 = new Base();
Base* ptr2 = new Derived1();
Base* ptr3 = new Derived2();
// calling all functions
ptr1->function1();
ptr1->function2();
ptr1->function3();
ptr2->function1();
ptr2->function2();
ptr2->function3();
ptr3->function1();
ptr3->function2();
ptr3->function3();
// deleting objects
delete ptr1;
delete ptr2;
delete ptr3;
return 0;
}
86
#include<iostream>
using namespace std;
class Person {
// Data members of person
public:
Person(int x) { cout << "Person::Person(int ) called" << endl; }
};
class Faculty : public Person {
// data members of Faculty
public:
Faculty(int x):Person(x) {
cout<<"Faculty::Faculty(int ) called"<< endl;
}
};
class Student : public Person {
// data members of Student
public:
Student(int x):Person(x) {
cout<<"Student::Student(int ) called"<< endl;
}
};
class TA : public Faculty, public Student {
public:
TA(int x):Student(x), Faculty(x) {
cout<<"TA::TA(int ) called"<< endl;
}
};
int main() {
TA ta1(30);
}
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1. Write a function swap two swap two numbers following these approaches:
a. Pass by value
b. Pass by address
c. Pass by reference
2. In the Person class add a static data member count and the following methods:
a. Default constructor
b. Parameterized constructor (Use this pointer )
c. Copy constructor
d. Static method DisplayCount
In the main method create an array of 5 objects and invoke all the appropriate methods.
Also create an object of this class dynamically using new and then delete it at run time.
3. Create a class Complex with data members real and imaginary
a. Default constructor
b. Parameterized constructor
c. Copy constructor
d. Static method DisplayCount
In the main method create an array of 5 objects and invoke all the appropriate methods.
Also create an object of this class dynamically using new and then delete it at run time.
4. Create a class Time with data members hh,mm,sec. Add the following methods:
a. Default constructor
b. Parameterized constructor
c. Copy constructor
5. Write a program to create a class player with members as Name,Id,Role, Avg runs, wkts taken and innings played. Create an array of 10 players and write functions to display information of player with maximum , maximum wkts takes.
6. Create a Class named Array with a pointer to integer as member. Allocate memory dynamically for this pointer in constructor. Write appropriate constructors (default, parameterized and copy). Also add destructor.
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