-
-
What is the use of delete operator in c++?
Amit
- Jan 6th, 2012
Delete: is used to deallocate memory from the heap that is created by new.
When you call delete, it firstly call the destructor of that object and then deallocate memory from heap.
class A
{
};
int
main()
{
A *a = new A();
delete a;
A *arr = new A[10];
delete []arr;
} -
Inheritance in C++
While doing inheritance in C++, one thing that is not inherited is what?
-
C/C++ black screen opens and closes
While executing a program in C++, it happens the black screen opens and closes automatically without displaying the output(program is correct). How to recover from this situation?
-
Read the following code and then implement the following parts:
Read the following code and then implement the following parts:
class Point {
public int xCoordinate;
public int yCoordinate;
}
1. Derive a class from Point and call it DerivedPoint, the new class will contain two constructors, the first one takes no arguments, it assigns the point to the point (1,1) and the second constructor takes two parameters...kladarak
- Nov 28th, 2015
danarusus answer was pretty much there, but there are a few things that could be improved with it. - Display() doesnt output x and y coords in exactly the format requested. There should be no space...
ThePurpleTwist
- Nov 12th, 2015
There is a mistake in the code submitted by chandra ;
DerivedPoint : public Point instead of "::" -
What is friend function?
As the name suggests, the function acts as a friend to a class. As a friend of a class, it can access its private and protected members. A friend function is not a member of the class. But it must be listed in the class definition.
charlie02
- Aug 9th, 2010
Friend function is a non-member function, which can?access the private member of a given class, only if it made as the friend of that class.
MCBod
- Mar 31st, 2010
A friend function is a special function that has been granted access to the priovate members of a specific class. The class itself is responsible for declaring the friendship. It is nto affected by in...
-
What is a scope resolution operator?
A scope resolution operator (::), can be used to define the member functions of a class outside the class.
keloth1987
- Nov 7th, 2011
You can tell the compiler to use the global identifier rather than the local identifier by prefixing the identifier with ::, the scope resolution operator. :: identifier class-name :: identifier name...
rajendra chaudhary
- Nov 1st, 2011
It is an operator :: used mainly in class for defining the member functions and also for accessing the global variables.
and it is a eye of c++. -
What is virtual class and friend class?
Friend classes are used when two or more classes are designed to work together and need access to each other's implementation in ways that the rest of the world shouldn't be allowed to have. In other words, they help keep private things private. For instance, it may be desirable for class DatabaseCursor to have more privilege to the internals of class Database than main() has.
sivakumar.v
- Jul 3rd, 2008
Virtual class :: It is an inner class which can be overriden by the derived classes.
SomGollakota
- May 25th, 2008
Answering amarendra.moharana's question.Amarendra, My apologies that it took so long to answer your question. Haven't logged in for quite a while.In class D of your example, you will still hav...
-
What is virtual constructors/destructors?
Virtual destructors: If an object (with a non-virtual destructor) is destroyed explicitly by applying the delete operator to a base-class pointer to the object, the base-class destructor function (matching the pointer type) is called on the object. There is a simple solution to this problem – declare a virtual base-class destructor. This makes all derived-class destructors virtual even...
-
-
What is importance of const. pointer in copy constructor?
Krishna Kumar
- Sep 25th, 2018
There is three query for the above question, 1) Why reference object passed as parameter to the copy constructor? 2) Why pointer object is not passed as parameter to the copy constructor? 2) What r...
WinSound
- May 31st, 2010
Copy constructor syntax:A(const A&) for the class "A"const - Indicates object passed as argument is not changed inside copy constructor so there may be 3 design possibliti...
-
Private Inheritance question
Hi I very recently did the C++ online Quiz and was surprised to find that my answer (1) to the following question (below) was incorrect. Is there something I am missing here, or is the answer incorrect. I thought this was the point of Private. "Always inaccessible regardless or derivation access".Apparently (3) in the correct answer! according to the quiz!The private member in derived class ...
j_l_larson
- Oct 19th, 2009
You can if the base class provides public or protected methods that modify its private data. Then derived class can expose this using access specifiers.
-
What is the difference between operator new and the new operator?
sachin_mundhra
- Dec 18th, 2009
Operator new works like malloc. Example:int *n; n = (int*) operator new(sizeof(int)); New Operator does the following:1) Calculate the memory 2) Allocate memory using operator new 3) Call the Constructor
satheesh83
- Oct 16th, 2009
New operator allows to allocate a memory from the heap, so a new instance of a class is created but operator New is used to overload the (new) operator just like overloading of other operators. A...
-
What is difference between followin intialization.int iVar1;int iVar2 = int();and which one of two should we prefer always and why?
mucdull
- Nov 17th, 2008
int iVar1; // iVar1 is never initializedint iVar2 = int(); // iVar2 will always be initialized with some initial valueThe latter should be used becaus...
Anil
- May 21st, 2007
Dependsif use in main both will get initialize to '0'.ie: global if use inside a function (local) iVar1 will be garbage, iVar2 will be initialised to '0';
-
How to multiply a varible x (int) by 7, without using multiplication & addition ?
bapu_60
- Feb 20th, 2008
Multiplication is a costly operation,costlier than bit operations.So,it is a better practice to use bit operation that is << for multiplication and >> for divsion when you are multiplying with a factor of 2 otherwise its not suggested.
praveennext
- Jan 3rd, 2007
This can be a generic solution for x*y without using *.while(y>>=1){if(y | 1) tot+=x; x<<=1; }or,for( ; y ; y>=1, x<<=1 ) if(y | 1) tot+=x;or even stupid like, while(x--) tot+=y; ;-)May be a brain teaser, but this may eat time.
-
What is virtual base class?
daljit.mca
- Aug 25th, 2010
Suppose you have two derived classes B and C that have a common base class A, and you also have another class D that inherits from B and C. You can declare the base class A as virtual to ensure that B and C share the same subobject of A.Dj.Maan
dasam
- Mar 29th, 2007
If we are working with multiple inheritance, it is always better to make the base class as virtual inorder to avoid the multiple copies of the base class data. :)
-
Explain why encapsulation is required?
Niranjan.ambati
- May 8th, 2009
Encpasulation is the process of packaging the classes into the public interfaces and private implementation,?so that, any changes in the code will not?effect the implmentation. The interfaces?shoul...
r v p
- May 7th, 2008
Encapsulation is an OOP principle of placing the data and functionality within a single entity. This is so that all the functions that access the internal representation of the data type must be part of the data type definition.
-
Why an empty Structure will occupy 2Bytes in C++
dkuy1
- Aug 9th, 2009
The Standard C++ language definition says: A class with an empty sequence of members and base class objects is an empty class. Complete objects and member sub-objects of an empty class type shall h...
-
What does this function do:
What does this function do:string f(const string &x) { return x.empty()? x : f(x.substr(1)) + x[0];}What does this piece of code perform:char *a=...., *b=....;while(*b++ = *a++);
shantanu_hbd
- Apr 25th, 2009
Second function is copying 'a' to 'b' provided that 'a' should be a null terminated string.
santhosh.kanchanapally
- Feb 17th, 2009
Char *a="hai", *b="san";while(*b++ = *a++);This program leads to crash, as we are assigning one memory location to other memory location.
-
C++ Interview Questions
Ans