const in class as a member variable?

sam_psycho

Is it possible to declare member variable of class as a const, if yes,please give me 1 example how to initialize it and if not, why?

Cedric Moonen

Yes, it is possible. You have to initialize it in the constructor initialization list:

MyClass::MyClass() : myConstInt(5)
{
}

You can also initialize it in the header file too, when declaring it:

class MyClass
{
const int myConstInt = 5;
}

Cédric Moonen Software developer
Charting control [v2.0] OpenGL game tutorial in C++

CPallini

sam_psycho wrote:

Is it possible to declare member variable of class as a const,

Yes.

sam_psycho wrote:

if yes,please give me 1 example how to initialize it

class A
{
static const int c = 299792458;
const int a;

A():a(5){}
};

:)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
[My articles]

sam_psycho

This is working fine

MyClass::MyClass() : myConstInt(5)
{
}

but it is not possible,

class MyClass
{
const int myConstInt = 5;
}

compiler is giving error, So I guess only one way to initialize const in a class..

Cedric Moonen

Ooops, my bad. I don't use that notation very often. I thought it was ok but it is only valid if the member is static also.

Cédric Moonen Software developer
Charting control [v2.0] OpenGL game tutorial in C++

sam_psycho

from above discussion I have come to conclusion that compiler does not allow any type of initialization in class, so statement

static const int c = 299792458;

in your code also creating problem... :(

CPallini

You're wrong (I'm right, of course... :rolleyes: ). It looks like you missed the static modifier. :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
[My articles]

sam_psycho

who is lying compiler or you?..but I should believe in compiler and it says that error: c:\test.cpp 6: cannot initialize class member here try this code

class temp
{
static const int i=10;
};
void main()
{
}

CPallini

I never lie. Anyway maybe your compiler follows strictly the C++ stanbdard. (my compiler doesn't complain, see [^]). :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong. -- Iain Clarke
[My articles]