C++ mark as deprecated

you could do this:

enum MyEnum {
    firstvalue = 0,
    secondvalue,
    thirdvalue, // deprecated
    fourthvalue
};
#pragma deprecated(thirdvalue)

then when ever the variable is used, the compiler will output the following:

warning C4995: 'thirdvalue': name was marked as #pragma deprecated

EDIT
This looks a bit hacky and i dont have a GCC compiler to confirm (could someone do that for me?) but it should work:

enum MyEnum {
    firstvalue = 0,
    secondvalue,
#ifdef _MSC_VER
    thirdvalue,
#endif
    fourthvalue = secondvalue + 2
};

#ifdef __GNUC__
__attribute__ ((deprecated)) const MyEnum thirdvalue = MyEnum(secondvalue + 1);
#elif defined _MSC_VER
#pragma deprecated(thirdvalue)
#endif

it's a combination of my answer and MSalters' answer

It makes it easier to generate source code, and also to write code which can be easily extended at a later date. Consider what's required to add an extra entry to:

int a[] = {
   1,
   2,
   3
};

... you have to add the comma to the existing line and add a new line. Compare that with the case where the three already has a comma after it, where you just have to add a line. Likewise if you want to remove a line you can do so without worrying about whether it's the last line or not, and you can reorder lines without fiddling about with commas. Basically it means there's a uniformity in how you treat the lines.

Now think about generating code. Something like (pseudo-code):

output("int a[] = {");
for (int i = 0; i < items.length; i++) {
    output("%s, ", items[i]);
}
output("};");

No need to worry about whether the current item you're writing out is the first or the last. Much simpler.