Creating a const in a class?

Hello cppers

I am converting a Java class to C++ and have this in a Java class:

public static final int APPLICATION = 0x40;

So in my C++ class I tried:

const int APPLICATION = 0x40;

which of course gives me a C2252 compile error.

How would I create the equivalent type of constant in a C++ class?

re: Creating a const in a class?

Angus skrev:Ouch! ;-)Why of course? The above declaration looks fine (but ugly: reserve all
uppercase for macroes).If you're using an old compiler (e.g. MSVC6), the following trick will
do:

enum { APPLICATION = 0x40 };

/Peter

re: Creating a const in a class?

Angus wrote:I'm assuming you're using one of the MS compilers, because of the
compile error you listed. Did you check the MSDN help about this
compiler error? There's a page with a solution for you:
http://support.microsoft.com/kb/241569

re: Creating a const in a class?

"peter koch" <peter.koch.larsen@gmail.comwrote in message
news:1167837650.850553.269740@a3g2000cwd.googlegro ups.com...Thanks. I assumed it was a language issue not a compiler limitation issue.

re: Creating a const in a class?

Angus wrote:You should never assume anything about an old compiler, which
actually predates the language Standard. And why are you using
such an old compiler, anyway? And what book on C++ are you
reading that doesn't describe class-wide integral constants?

V
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re: Creating a const in a class?

Angus wrote:If you're trying to define a const inline in a class definition, it must
be a *static* const member of intergral or enum type.

i.e.

static const int APPLICATION = 0x40;

re: Creating a const in a class?

On Wed, 03 Jan 2007 15:14:22 +0000, Angus wrote:
Don't forget to define a static const int by writing:

const int my_clas::APPLICATION;

re: Creating a const in a class?

Philipp Reh wrote:That's only needed if it's used as an lvalue (e.g. its address is
taken).

V
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re: Creating a const in a class?

From C++ FAQs book

class Fred {
public:
Fred(int i) throw();
Fred(int i, int j) throw();
protected:
int i_;
const int j_;
};

Fred::Fred(int i) throw(): i_(i), j_(10)
<-- 1
{ }

Fred::Fred(int i, int j) throw(): i_(i), j_(j)
<-- 2
{ }

int main()
{
Fred a(5); //a.j_ will always be 10
Fred b(5,15); //b.j_ will always be 15
Fred c(5,20); //c.j_ will always be 20
}



"Angus" <nospam@gmail.comwrote in message
news:engh8l$84p$1$8300dec7@news.demon.co.uk...

re: Creating a const in a class?

On Jan 3, 4:14 pm, "Angus" <nos...@gmail.comwrote:just type static int APPLICATION = 0x40

re: Creating a const in a class?

This is what I normally do. Although the enum trick saves typing.

//IN HEADER FILE
class Example {
private:
static const int COLD_DAYS; //This could be public or private

public:
void printColdDays();
}

//IN IMPLEMENTATION (.cpp file)

#include <iostream>
const int Example::COLD_DAYS = 79;

void Example::printColdDays() {
std::cout << "There are " << COLD_DAYS << " cold days." << endl;
}

//IN MAIN FUNCTION
Example badName;
badName.printColdDays();