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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...
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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...
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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...
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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.
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Difference between realloc() and free()?
The free subroutine frees a block of memory previously allocated by the malloc subroutine. Undefined results occur if the Pointer parameter is not a valid pointer. If the Pointer parameter is a null value, no action will occur. The realloc 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...
SomGollakota
- Jun 13th, 2007
free() - releases the memory of the pointer passed as parameter, to the OS/application consumption. Using the pointer after free() will result in undefinded resultsrealloc() - used to resize the memor...
Roopesh Majeti
- May 27th, 2007
Mitra,as you mentioned that realloc will delete the existing memory and allocate the new memory . I tried it on solaris and following is found :1. If the new size allocated is less than the existing m...
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What do you mean by inline function?
The idea behind inline functions is to insert the code of a called function at the point where the function is called. If done carefully, this can improve the application's performance in exchange for increased compile time and possibly (but not always) an increase in the size of the generated binary executables.
Sampada Wadkar
- Apr 9th, 2012
An Inline function is a function that is expanded in line when it is invoked. That is compiler replaces the function call with the corresponding function code.. :)
Code- CO06203
MCBod
- Mar 31st, 2010
An inline function is a function where a copy of the logic is embedded in the application at each the point where it is called by the compiler. This basically allows a reduced overhead in function dereferencing
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What is the difference between a pointer and a reference?
sachin_mundhra
- Jan 28th, 2010
Pointer can be NULL but reference cannot be NULL.For example, If you write int &a; // This will give compile error, because reference cannot be NULL.
pammi_11
- May 10th, 2008
Pointer holds the address of a variable.reference holds the address of duplicate of that variable.
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What is the need /use of function overloading
Hint FO is mechanism in which two functions r having same name with diff no. of arguments.
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What is the difference between static global variable and static local variable?
yzesong
- Jul 31st, 2009
They have almost same lifetime(local is shorter), but different access scope.
burraganesh
- Dec 7th, 2008
For both these the default initial value is 0A static global variable can only be accessed in the file it exists, we cannot use it in other files, even after mentioning it as externIn static local var...
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How will you detect if there is memory leak in your C++ program?
vijay.badola
- Oct 4th, 2009
In LINUX environment one can use VALGRIND and MPATROL free tools to find out possible memory leaks in programs.
santhosh.kanchanapally
- Feb 18th, 2009
By overloading the new and delete operators, we can find the memory leaks as shown in following program ,#include "stdafx.h"#include <iostream>#include <string>using namespace st...
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Inheritance
What is inheritance? why we use it? plzz can anybody explain me with one example and where we use that concept?
navneet.navu
- Apr 19th, 2010
It is an object oriented feature which provides the reusablity of code. All the properties defined in the parent class can be used by its child classes without writing the code again.
Samuel Rengarajan
- Dec 11th, 2009
All Common features are come to parent class. So we can extend this class to child classes. Child classes contais some special features.Useage of inheritance : it reduce the code. If we use inheritance, we avoid redundent code.
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Inline Function Advantages
What are the advantages of inline functions over macros?
ashwin2090
- Aug 28th, 2009
Inline function very much confused to use it or not.Well I want to just tell you that it has large number of disadvantages than advantages Inline function works faster than normal function. They are ...
AnisHasan
- Jul 16th, 2009
Beside the adventages which are mentioned there are some more advantages of Inline Functions over Macros1> Macro call is resolve at the compile time and compiler replce Identifier with charecter se...
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Placement New Syntax
How can a C++ developer use the placement new syntax to make new allocate an object of class SomeClass at a particular memory address stored in a pointer type variable named pmem?A. new SomeClass(pmem);B. new(pmem) SomeClass;C. new SomeClass pmem;D. new pmem SomeClass;E. new (pmem, SomeClass);
ajrobb
- Sep 22nd, 2010
BWhere you use placement new, it is important to explicitly call the destructor for the object before re-using the memory.Fred * fred = new(pmem) Fred();...fred->~Fred();fred = 0;George * george(pmem) George();
akash_saxena
- Dec 22nd, 2009
It is B. new(pmem) SomeClass;pmem points to the memory which shall be used.
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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;
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Inheritance in C++
While doing inheritance in C++, one thing that is not inherited is what?
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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?
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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 "::" -
Why Pointers are not used in C Language. What are the main differences between C and C++
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