Programming C++
Consider the following code:
#include
using namespace std;
int main()
{
cout
What will be the result when the above code is
compiled and executed?
Correct answer is:
c. The code will compile and run without errors
Base class members are made accessible to a
derived class and inaccessible to rest of the
program by _____.
Correct answer is:
protected access specifier
Which of the following is not a standard STL
header?
Correct answer is:
a.
Which of the following are true about class and
struct in C++:
Correct answer is:
In a class all members are private by default,
whereas in struct all members are public by
default
Consider the following code:
#include
using namespace std;
class A
{
public :
A()
{
cout
What will be the printed output?
Correct answer is:
Constructor of A Constructor of B Destructor of B
Destructor of A
Consider the following code:
class A {
typedef int I; // private member
I f();
friend I g(I);
static I x;
};
Which of the following are valid:
Correct answer is:
a. A::I A::f() { return 0; }
b. A::I g(A::I p = A::x);
c. A::I g(A::I p) { return 0; }
d. A::I A::x = 0;
In the given sample Code, is the constructor
definition valid?
class someclass
{
int var1, var2;
public:
someclass(int num1, int num2) : var1(num1),
var2(num2)
{
}
};
Correct answer is:
a. Yes, it is valid
Which of the following STL classes is deprecated
(ie should no longer be used)
ostrstream
ostringstream
ostream
wostream
Correct answer is:
ostrstream
Which of the following statements are true about
C++ vector class?
a. vector::empty deletes all elements of the vector
b. vector::erase can be used to delete a single
element and a range of elements of the vector
c. After calling, vector::erase causes some of the
iterators referencing the vector to become invalid
d. vector::count returns the number of elements
in the vector
e. vector::size returns the number of elements in
the vector
f. vector::capacity returns the number of elements
in the vector
Correct answer is:
b. vector::erase can be used to delete a single
element and a range of elements of the vector
c. After calling, vector::erase causes some of the
iterators referencing the vector to become invalid
e. vector::size returns the number of elements in
the vector
Consider the following code:
class BaseException
{
public:
virtual void Output()
{
cout
Invoking Exception Test will result in which
output?
Correct answer is:
c. Unknown Exception Thrown
What will be the output of the following code?
class b
{
int i;
public:
virtual void vfoo()
{
cout
p = &ob2;
p->vfoo();
}
Correct answer is:
b. Base Derived
Report bad answer
What will be the output of the following code?
class A
{
public:
A():pData(0){}
~A(){}
int operator ++()
{
pData++;
cout
Correct answer is:
b. In second 1 In first 2
Consider the following class hierarchy:
class Base
{
}
class Derived : private Base
{
}
Which of the following are true?
Correct answer is:
d. Derived can access public and protected
member functions of Base
Consider the sample code given below and
answer the question that follows.
class A
{
public:
A() {}
~A()
{
cout
How many times will "in destructor" be output
when the above code is compiled and executed?
Correct answer is:
d. A compile time error will be generated because
destructors cannot be called directly
Consider the sample code given below and
answer the question that follows.
class SomeClass
{
int x;
public:
SomeClass (int xx) : x(xx) {}
};
SomeClass x(10);
SomeClass y(x);
What is wrong with the sample code above?
Correct answer is:
e. The code will compile without errors
A pure virtual function can be declared by _______.
a. equating it to 1
b. equating it to 0
c. equating it to NULL
d. the 'pure' keyword
e. the 'abstract' keyword
Correct answer is:
b. equating it to 0
Consider the sample code given below and
answer the question that follows:
char **foo;
/* Missing code goes here */
for(int i = 0; i <>
Referring to the sample code above, what is the
missing line of code?
Correct answer is:
d. foo = new char*[200];
Consider the following code:
class BaseException
{
public:
virtual void Output()
{ cout
Invoking Exception Test will result in which
output?
Correct answer is:
b. Derived Exception
Which of the following is a function that returns a
non zero value to indicate an I/O stream error?
a. bad
b. good
c. fail
d. eof
e. err
f. error
g. filerror
h. None of the above
Correct answer is:
h. None of the above
Consider the sample code given below and
answer the question that follows.
class Shape
{
public:
virtual void draw() = 0;
};
class Rectangle: public Shape
{
public:
void draw()
{
// Code to draw rectangle
}
//Some more member functions.....
};
class Circle : public Shape
{
public:
void draw()
{
// Code to draw circle
}
//Some more member functions.....
};
int main()
{
Shape objShape;
objShape.draw();
}
What happens if the above program is compiled
and executed?
Correct answer is:
e. None of the above
Consider the code given below and answer to the
question.
#include
using namespace std;
class b
{
int i;
public:
void vfoo()
{ cout
p = &ob2;
p->vfoo();
ob2.vfoo();
}
Correct answer is:
In Base In Base In Derived
Which of the following statements about
constructors and destructors are true?
a. In a given class, constructors are always
required to be defined, but destructors are not
b. Neither constructors nor destructors can take
parameters
c. Constructors can take parameters, but
destructors cannot
d. It is illegal to define a destructor as virtual
e. It is illegal to define a constructor as virtual
f. Both explicitly declared constructors and
explicitly declared destructors are required in a
class
Correct answer is:
c. Constructors can take parameters, but
destructors cannot
e. It is illegal to define a constructor as virtual
Consider the following class hierarchy:
class Base
{
}
class Derived : public Base
{
}
Which of the following are true?
Correct answer is:
d. Derived can access public and protected
member functions of Base
e. The following line of code is valid: Base *object
= new Derived();
Consider the sample code given below and
answer the question that follows.
template Run;
Which one of the following is an example of the
sample code given above?
Correct answer is:
c. A template function declaration
Consider the sample code given below and
answer the question that follows.
class X {
int i;
protected:
float f;
public:
char c;
};
class Y : private X { };
Referring to the sample code above, which of the
following data members of X are accessible from
class Y
Correct answer is:
a. c
b. f
Consider the following statements relating to
static member functions and choose the
appropriate options:
1. They have external linkage
2. They do not have 'this' pointers
3. They can be declared as virtual
4. They can have the same name as a non-static
function that has the same argument types
Correct answer is:
c. Only 1 and 2 are true
Which of the following operators cannot be
overloaded?
a. +=
b. >>
c. <>
Correct answer is:
d. .
e. ::
h. ?:
Consider the sample code given below and
answer the question that follows.
class Person
{
string name;
int age;
Person *spouse;
public:
Person(string sName);
Person(string sName, int nAge);
Person(const Person& p);
Copy(Person *p);
Copy(const Person &p);
SetSpouse(Person *s);
};
Which one of the following are declarations for a
copy constructor?
Correct answer is:
d. Person(const Person &p);
State which of the following is true.
a. Function templates in C++ are used to create a
set of functions that apply the same algorithm to
different data types
b. Classes in C++ are used to develop a set of
type-safe classes
c. C++ is useful for developing collection classes
d. C++ is useful for developing smart pointers
e. All of the above
Correct answer is:
e. All of the above
What is true about Function?
a. Functions can be overloaded
b. Functions can return the type void
c. Inline functions are expanded during compile
time to avoid invocation overhead
d. You can create arrays of functions
e. You can pass values to functions by reference
arguments
f. You can return values from functions by
reference arguments
g. A function can return a pointer
Correct answer is:
d. You can create arrays of functions
Which of the following techniques should you use
to handle a constructor that fails?
a. Return an error code from the constructor
b. Throw an exception from the constructor
c. Write the error to a log file
d. Use "delete this;" in the constructor
e. None of the above
Correct answer is:
b. Throw an exception from the constructor
What access specifier allows only the class or a
derived class to access a data member?
a. private
b. protected
c. default
d. virtual
e. public
Correct answer is:
b. protected
Consider the following code:
#include
int main(int argc, char* argv[])
{
enum Colors
{
red,
blue,
white = 5,
yellow,
green,
pink
};
Colors color = green;
printf("%d", color);
return 0;
}
What will be the output when the above code is
compiled and executed?
Correct answer is:
d. 7
Which of the following are NOT valid C++ casts?
a. dynamic_cast
b. reinterpret_cast
c. static_cast
d. const_cast
e. void_cast
Correct answer is:
e. void_cast
Consider the code given below and refer to the
question.
class BaseException
{
public:
virtual void Output()
{
cout
Invoking Exception Test will result in which
output?
Correct answer is:
a. Base Exception
Which of the following is NOT a standard sorting
algorithm:
a. std::sort
b. std::qsort
c. std::stable_sort
d. std::partial_sort
Correct answer is:
b. std::qsort
How many arguments can be passed to an
overloaded binary operator?
a. 4
b. 3
c. 2
d. 1
e. 0
Correct answer is:
d. 1
Which of the following is a predefined object in C+
+ and used to insert to the standard error output?
a. std::err
b. std::error
c. std::cerror
d. std::cerr
e. std::cin
f. std::clog
Correct answer is:
d. std::cerr
Which of the following statements are true?
a. Inline functions should be preferred over
macros because inline functions have better
performance
b. Macro usage should be avoided because they
are error prone
c. Normal functions should be preferred over
macros because normal functions have better
performance
d. Macro usage should be avoided because
macros do no perform type checking
e. Inline functions should be preferred over
macros because inline functions perform type
checking
Correct answer is:
b. Macro usage should be avoided because they
are error prone
d. Macro usage should be avoided because
macros do no perform type checking
e. Inline functions should be preferred over
macros because inline functions perform type
checking
Consider the sample code given below and
answer the question that follows.
class Outer
{
public:
class Inner
{
int Count;
public:
Inner(){};
};
};
int main()
{
Inner innerObject;
Outer outObject;
return 0;
}
What will be the result when the above code is
compiled?
Correct answer is:
d. There will be an error because in the
declaration of innerObject the type Inner must be
qualified by Outer
Consider the sample code given below and
answer the question that follows.
1 class Car
2 {
3 private:
4 int Wheels;
5
6 public:
7 Car(int wheels = 0)
8 : Wheels(wheels)
9 {
10 }
11
12 int GetWheels()
13 {
14 return Wheels;
15 }
16 };
17 main()
18 {
19 Car c(4);
20 cout
Correct answer is:
e. 19
What is the output of the following code segment?
int n = 9;
int *p;
p=&n;
n++;
cout
Correct answer is:
c. 12,10
Which of the following statements are FALSE with
regard to destructors?
a. A derived class can call the destructor of the
parent class explicitly
b. A class may have only one destructor
c. Destructors cannot be invoked directly
d. The return type for a destructor is void
e. Destructors cannot accept arguments
Correct answer is:
a. A derived class can call the destructor of the
parent class explicitly
If a matching catch handler (or ellipsis catch
handler) cannot be found for the current
exception, then the following predefined runtime
function is called ______.
a. abort
b. set_terminate
c. terminate
d. close
Correct answer is:
c. terminate
Sample Code
typedef char *monthTable[3];
Referring to the code above, which of the
following choices creates two monthTable arrays
and initializes one of the two?
Correct answer is:
e. monthTable winter,spring=
{"March","April","May"};
What happened when the following code is
compiled and executed?
#include
using namespace std;
class myclass
{
private:
int number;
public:
myclass()
{
number = 2;
}
int &a()
{
return number;
}
};
int main()
{
myclass m1,m2;
m1.a() = 5;
m2.a() = m1.a();
cout
return 0;
}
Correct answer is:
b. The printed output will be 5
Which of the following member functions can be
used to add an element in an std::vector?
a. add
b. front
c. push
d. push_back
Correct answer is:
a. add
Which of the following techniques should you use
to handle a destructor that fails?
a. Return an error code from the destructor
b. Throw an exception from the destructor
c. Write the error to a log file
d. Use "delete this;" in the destructor
e. None of the above
Correct answer is:
c. Write the error to a log file
Which of the following are NOT valid C++ casts?
a. dynamic_cast
b. reinterpret_cast
c. static_cast
d. const_cast
e. void_cast
Correct answer is:
e. void_cast
In C++, the keyword auto can be used for:
a. Automatic assignment of data to objects during
instantiation
b. Automatic call of a function
c. Declaration of a local variable
d. Automatically erasing an object when it is no
longer needed
e. Automatic handling of run-time errors in the
program
f. Automatic termination of a program in case the
user does not respond within a given time period
g. Automatic creation of variables
Correct answer is:
c. Declaration of a local variable
Which of the following statements are true for
operator overloading in C++?
a. The * operator can be overloaded to perform
division
b. The * operator can be overloaded to perform
assignment
c. ** can be overloaded to perform "to the power
of"
d. Operators can be overloaded only in inside
classes
e. Operators can be overloaded globally
Correct answer is:
a. The * operator can be overloaded to perform
division
b. The * operator can be overloaded to perform
assignment
c. ** can be overloaded to perform "to the power
of"
d. Operators can be overloaded only in inside
classes
Unary operator, overloaded by means of a friend
function take one reference argument.
Correct answer is:
a. True
If input and output operations have to be
performed on a file, an object of the _______ class
should be created.
a. fstream
b. iostream
c. ostream
d. istream
e. None
Correct answer is:
a. fstream