what is a static class

kumar_mk

is there any thing like static class in c++ thank u kk.

toxcct

static class, no. static instance of a class yes. please explain where you heard this, and what you want to be detailed...

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Cedric Moonen

kumar_windows wrote:

is there any thing like static class in c++

What do you mean exactly ? Can you be more explicit and explain what you want to do exactly ? Yes, you can declare a class static like any other variable but I don't know if this is what you are looking for.

Cédric Moonen Software developper
Charting control -- modified at 9:43 Friday 12th May, 2006 Sorry, not very clear :~ . As toxxct said (and what I meant by saying that) is declaring an instance of a class static, not the class itself

toxcct

Cedric Moonen wrote:

Yes, you can declare a class static like any other variable

actually, you're not declaring the class static but the instance of the class...

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Cedric Moonen

Yes, my post has already been modified :-D. It's friday afternoon so my english skills tend to decrease :doh:

Cédric Moonen Software developper
Charting control

toxcct

Cedric Moonen wrote:

Sorry, not very clear . As toxxct said

damn, toxcct, not toxxct ;P think to "toxicity" if that can help... anyway, ok, friday afternoon... hehehe

TOXCCT >>> GEII power

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Cedric Moonen

Do you think it's easy not to make mistakes while typing with your nose ? :rolleyes:

Cédric Moonen Software developper
Charting control

toxcct

arg, you're right, those letters are too close :doh:

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ThatsAlok

Cedric Moonen wrote:

while typing with your nose ?

Again Nose:)

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ThatsAlok

kumar_windows wrote:

is there any thing like static class in c++

Are you looking something like SingleTon Classes[^]?

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers, Alok Gupta VC Forum Q&A :- I/ IV

kumar_mk

hello toxcct, it was asked to me in an interview, u r saying we have a static class , like static class A{ ----- }; and if i create an object for it what happens??? kk

kumar_mk

hello cedric, it was an interview question, u mean to say i can declare a class as static like static class A{----}; what is its purpose, please elaborate on single instance of a class, u mean when i create an object for this class thanks kk

kumar_mk

hi alok, no not a singleton class, it was an interview question abt the static class, do we have it just like a static member variable and static function, wat is its significance/purpose?? can i create an object for this static class?? wat happens? thank u, kk

toxcct

dude !!! didn't you read what i said, or didn't you understand ? when i say you cannot define a class as static, it means that you CANNOT define a class like you do :

static class CFoo { // No !!! compilation error
// You cannot apply the static keyword to a type definition
//...

};

what i said however is that you are allowed to declare an instance of a class as static, that means a variable which type is a user-defined type :

#include "Foo.h"

static CFoo foo; // Allowed ! foo variable of type CFoo is static

now, what don't you understand ? you'd certainly google the internet or even better, search a good C++ book for static concept...

TOXCCT >>> GEII power

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Maxwell Chen

The code snipet below demonstrates the variable instance obj to be static not the type Type, even though it would be confusing you.

#include <iostream>

int main()
{
static class Type
{
public:
void Hello() { std::cout << "Type::Hello() \n"; }
} obj;
obj.Hello();
return 0;
}

Which is equivelent to:

#include <iostream>

int main()
{
class Type
{
public:
void Hello() { std::cout << "Type::Hello() \n"; }
};
static Type obj;
obj.Hello();
return 0;
}

Maxwell Chen

toxcct

i hesitated to show off this example, but finally didn't, thinking it would confuse most beginners around. by the way, it is perfectly legal to do so, as we declare a variable with the type definition inlined...

TOXCCT >>> GEII power

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Maxwell Chen

And a further example to demonstrate that the member variables are not shared among individual static instances.

#include <iostream>

static class Type
{
int v;
public:
void Hello() {
std::cout << "Type::Hello() \nv = " << v << " \n";
}
void Hello(int n) {
v = n;
std::cout << "Type::Hello(" << v << ") \n";
}
} g_obj, g_objx;

int main()
{
std::cout << "g_obj \n";
g_obj.Hello(3);
g_obj.Hello();
std::cout << "g_objx \n";
g_objx.Hello();
return 0;
}

The output goes to:

g_obj
Type::Hello(3)
Type::Hello()
v = 3
g_objx
Type::Hello()
v = 0

Maxwell Chen

Stephen Hewitt

C# has the concept of a static class: a static class is a class that contains only static members and instances can't be created with the new keyword. C++ has no such concept; although you can create classes with only static members you do so explictly and the compiler will not stop you from adding a non-static member. Steve

ThatsAlok

kumar_windows wrote:

u r saying we have a static class , likestatic class A{ ----- };and if i create an object for it what happens???

Dude There is nothing like Static class, as class doesnot have any address till is object is created, so how can you make anything static which doesn't exist till it object is created

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers, Alok Gupta VC Forum Q&A :- I/ IV

Nemanja Trifunovic

kumar_windows wrote:

is there any thing like static class in c++

No.

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