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Register Relation
Why p++ is faster than p+1?
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sahasranaman- Member Since Jul-2009 | Jul 1st, 2009
p++ is faster because on compilation, it gets translated to three machine instructions, where as p=p+1 needs four machine instructions. All machine instructions take the same time.
For p++, the instructions are:
mov ax,
inc ax
mov,
axFor p = p+ 1, the instructions would be,
mov ax,
mov bx, 1
add bx
mov,
axThis is why p++ is faster than p+1
Mann2920
- Jan 24th, 2011
To perform?i+1?complier has to do:1-Addition i+12-Assignment i=result of additionWhile in case of i++Value is simply increased by 1so i++ is faster
Gargona
- Feb 13th, 2010
Difference in assembler code:--$ diff -uN a2.S a.S--- ++p.S 2010-02-13 15:51:09.000000000 +0200+++ p+1.S 2010-02-13 15:50:30.000000000 +0200@@ -6,7 +6,6 @@&nb...
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What is public, protected, private?
Public, protected and private are three access specifiers in C++. 1. Public data members and member functions are accessible outside the class.2. Protected data members and member functions are only available to derived classes.3. Private data members and member functions can’t be accessed outside the class. However there is an exception can be using friend classes.
ankit
- Jun 26th, 2015
Can we use protected specifier first than public than private in a class definition in c++ by making class
KomalUpadhyay
- Nov 14th, 2009
Private Protected and Public all these are access specifiers.Private Data Members are only available inside classProtected Data Members are only available inside class as well as in derived classes.Public Data members are available everywhere
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Explain how static class member initialized?
sachin_mundhra
- Jan 28th, 2010
Example :- class Base{public:static int data;};int Base :: data = 10 ; // static class member gets initialized.
yzesong
- Jul 31st, 2009
Static variables of a class can only be initialized like this CLASS_NAME::STATIC_VAR_NAME = VAR_VALUE;
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VTable is same for all objects of class. That means it is stored in memory . Can we obtain the address of VTable without creating any object of class?
jwent
- Aug 14th, 2008
Each instance of a class has its own vtable. Its not a predefined place in memory.
wael.salman
- Jul 30th, 2008
When an object is created, a pointer to this vtable, called the virtual table pointer or vpointer, is added as a hidden member of this object (often the first member). The compiler also generates &quo...
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C++ program to expand the given string
C++ program to expand the following string
aa2b4c3d
o/p should be :
aabbccccddd -
What is an object?
Object is a software bundle of variables and related methods. Objects have state and behavior.
srabani_mazumder
- Aug 30th, 2010
The term object means a combination of data and logic that represents some real world entity.
rajangidwani
- Jul 20th, 2009
An object is an instance of the class through which we can access the methods and class variables
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Can destructor be private?
NikunjSingh
- Feb 23rd, 2012
Destrcutors can be made private to stop user from creating objects on stack. One can still create objects on stack using a static function as member function. But if intention is not to let user crea...
mehulgala177
- Sep 22nd, 2011
YESSSS destructors can be private. Infact this concept is used in Singleton design pattern. So, outsiders cannot delete object of that class. It has to b deleted from the class itself. I know...I...
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It possible to inherit the private member in drived class?
SomGollakota
- Jun 13th, 2007
Inheritance is one thing, access is quite another. For a C++ class,1. Private members - are off limites to everyone except the ones that are declared in one way or the other, inside the class (direct ...
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What are the disadvantages of C++?
ishanaditya
- Sep 1st, 2014
There is nothing really wrong with C++ anymore. The few reservations I had personally have been fixed with the latest C++11 standard: - C++ wasnt really designed for writing multithreaded application...
robertgbjones
- Aug 5th, 2014
Compared to what? C++ is a potentially low-level, close to the metal language, so potential for performance, though perhaps not as much as assembler, conversely its quite hard to learn, and now a big ...
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The following code results in class eg { void ml( ) {int i = 6; for {int i=5: i< 10;i ++ } { if{i==6} continue; system.out.println {i} ; } } ; } 1. syntax / compilation error 2. 5 6 7 8 9 3. 6 7 8 9 4. 5 7 8 9
talktome.ruchi
- Sep 23rd, 2011
The correct answer is option 4, since the scope of both the i's are different so we can declare it multiple times
anabarai
- Jul 4th, 2011
If you see the for for block:
for {int i=5: i< 10;i ++ }
you will see that it has a semi colon after the int i=5 which results in a syntax error. so the answer would be 1. syntax/compilation error -
Why size of an empty function is 5?
rahilchoudhary
- Sep 28th, 2010
There is no function to calculate the size of a function.And this 5 value of an empty function is a myth.Certain working programs can even have size of 4.Regards
ajrobb
- Sep 22nd, 2010
It isn't.#include <iostream>void f() {}int main() { std::cout << sizeof f() << 'n'; // fails to compile on g++ because return is void std::cout << sizeo...
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What are Virtual Functions? How to implement virtual functions in "C"
kamranahmad
- May 26th, 2008
Hi here i have more simplified example Hope this will give you clear view and check this linkhttp://www.codersource.net/published/view/325/virtual_functions_in.aspx#include <stdio.h>#include <...
SomGollakota
- Apr 21st, 2008
Sukesh, Your response is essentially correct if we are talking about pure virtual functions. However, when we talk about virtual functions, then we perhaps need to make a distinction between regu...
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What is out put of C++ code?
cclass base
{
public:
virtual void display(int i = 10)
{
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What is the difference between c&c++?
pammi_11
- May 31st, 2008
c is a procedural language. where as c++ is object oriented programming language.
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Inheritance
Which one of the following statements regarding C++ class inheritance is FALSE?
a. Inheritance promotes generic design and code reuse.b. Struct cannot be inherited in C++.
c. C++ supports multiple inheritance. d. Inheritance is a mechanism through which a subclass inherits the properties and behavior of its superclass.abhimanipal
- Feb 21st, 2010
The above answers are wrong. structs can be inherited in C++ . The only point to note is that for structs the defualt mode of inheritance for structs is public but for classes its private
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What is a class?
Class is a user-defined data type in C++. It can be created to solve a particular kind of problem. After creation the user need not know the specifics of the working of a class.
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Answered by: hirma
- Sep 18th, 2005
class is a userdefined datatype which consists of attributes(datamembers) and behavior(member functions).Bydefault the members of a class is private.
Nikita
- Jan 23rd, 2018
Class is a user define data type which contains the variable and function which r of two type private and public where the public class members can be accessed from any other class but the private cla...
Atul
- Dec 18th, 2017
Class is same as structure in C, but in Class we have functions
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How to create an object for a class that hasa constructor defined under privete access specifier
Prasad2008
- Jun 10th, 2008
There was little error in the code in my previous answer. We have to define a public static member function for this purpose. Here is the codeclass sample{sample* p;sample();public:static s...
Prasad2008
- Jun 10th, 2008
We have to define a public static member function for this purposeclass sample{sample* p;sample();public:static sample genObject();};sample* sample::genObject(){p=new sample;return p;}void main(){sample *p1=sample::genObject();}
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What is polymorphism? Explain with an example?
"Poly" means "many" and "morph" means "form". Polymorphism is the ability of an object (or reference) to assume (be replaced by) or become many different forms of object. Example: function overloading, function overriding, virtual functions. Another example can be a plus ‘+’ sign, used for adding two integers or for using it to concatenate two strings.
C++ Interview Questions
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