Question 1

What is function prototype in C++?

Accepted Answer

A function prototype is a declaration of a function that omits the function body It specifies the function’s name, argument types and return type Eg int add(int,int)

Question 2

Define Structure in C++.?

Accepted Answer

The C++ programming technique allows defining user defined datatypes through structure The syntax to declare structure is as follows: struct student { char name[100] char address[250] };

Question 3

What do you mean by reference variable in c++?

Accepted Answer

A reference variable provides an alias to a previously defined variable Data type & reference-name = variable name

Question 4

How many ways are there to initialize int with a constant?

Accepted Answer

There are two formats for initializers in C++ as shown in the example that follows. The first format uses the traditional C notation. The second format uses constructor notation. int foo = 123; int bar (123);

Question 5

What is an explicit constructor?

Accepted Answer

A conversion constructor declared with the explicit keyword The compiler does not use an explicit constructor to implement an implied conversion of types It’s purpose is reserved explicitly for construction

Question 6

How many ways of reusing are there in class hierarchy?

Accepted Answer

Class hierarchies promote reuse in two ways. They are code sharing and interface sharing.

Question 7

What is meant by exception specification?

Accepted Answer

C++ provides a mechanism to ensure that a given function is limited to throwing only a specified list of exceptions. It is called as exception specification.

Question 8

Which operator is used in catch-all handler?

Accepted Answer

The ellipses operator can be represented as (…).

Question 9

To which type of class, We can apply RTTI?

Accepted Answer

RTTI is available only for classes which are polymorphic, which means they have at least one virtual method.

Question 10

What do vectors represent?

Accepted Answer

Vectors are sequence containers representing arrays that can change in size.

Question 11

What is mandatory for designing a new container?

Accepted Answer

Iterators

Question 12

Explain one-definition rule (ODR).

Accepted Answer

According to one-definition rule, C++ constructs must be identically defined in every compilation unit they are used in As per ODR, two definitions contained in different source files are called to be identically defined if they token-for-token identical The tokens should have same meaning in both source files Identically defined doesn’t mean character-by-character equivalence Two definitions can have different whitespace or comments and yet be identical

Question 13

What are the advantages of using friend classes?

Accepted Answer

- Friend classes are useful when a class wants to hide features from users which are needed only by another, tightly coupled class - Implementation details can be kept safe by providing friend status to a tightly cohesive class

Question 14

.What are Stacks? Give an example where they are useful.

Accepted Answer

A Stack is a linear structure in which insertions and deletions are always made at one end ie the top - this is termed as last in, first out (LIFO) Stacks are useful when we need to check some syntex errors like missing parentheses

Question 15

Exlpain STL.

Accepted Answer

STL stands for Standard Template Library It is a library of container templates approved by the ANSI committee for inclusion in the standard C++ specification

Question 16

What is a Wrapper class?

Accepted Answer

Wrapper classes wrap primitive values in a class and offers utility to access them through objects Some of the primitive wrapper data types are: Byte, short, int, long, float, double, char, Boolean Example: Create a class name VectorAdd to populate it with integer values using the add(int, object) method public class VectorAdd { public static void main(String argv[]) { Vector v = new Vector(); vadd(0,new Integer(10)); vadd(1,new Integer(20)); vadd(2,new Integer(30)); for(int i=0; i < vsize();i ++) { Integer iw =(Integer) vget(i); Systemoutprintln(iw); } } }

Question 17

What do you mean by stack unwinding?

Accepted Answer

Stack unwinding is a process of calling all destructors for all automatic objects constructed at run time when an exception is thrown Destructors are called between the places where the exception was thrown and where it is caught

Question 18

Difference between Stack and Queue

Accepted Answer

Stack is a collection of objects that works in LIFO (Last in First out) mechanism while Queue is FIFO (First in First out) This means that the object that is inserted first is removed last in a stack while an object that is inserted first is removed first in a queue

Question 19

What is the scope resolution operator?

Accepted Answer

Scope resolution operator allows a program to reference an identifier in the global scope that is hidden by another identifier with the same name in the local scope

Question 20

Differentiate between realloc() and free().

Accepted Answer

- Free() - A block of memory previously allocated by the malloc subroutine is freed by free subroutine Undefined results come out if the Pointer parameter is not a valid pointer If the Pointer parameter is a null value, no action will take place - Realloc() - This subroutine changes the size of the block of memory pointed to by the Pointer parameter to the number of bytes specified by the Size parameter and returns a new pointer to the block The pointer specified by the Pointer parameter must be created with the malloc, calloc, or realloc subroutines and should not be deallocated with the free or realloc subroutines Undefined results show up if the Pointer parameter is not a valid pointer

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