Re: const parameter
On Apr 26, 8:52 pm, W Marsh <wayne.ma...@gmail.com> wrote:
Could anybody tell me wh the parameter "T val" is not marked
const in this Stroustrup code, considering that val is not
modified and not non- const methods called?
template<class C, class T> int count(const C&v, T val)
{
typename C::const_iterator i = find(v.begin(), v.end(), val);
int n = 0;
while (i != v.end()) {
++n;
++i; // skip past the element we just found
i = find(i, v.end(), val);
}
return n;
}
Because there's no real point in it? The const would be ignored
at the interface level (in the function declaration). One can
argue both ways in the function definition, but in practice,
very few if any programmers use const here.
The argument for the const is that you'll get an error if you
accidentally modify the variable. The argument against is: who
cares? It's your variable, and you should be able to do what
you want with it. There's also the argument that you don't want
the meaningless const in the declaration, and you want the
declaration and the definition to be coherent. (This argument
probably applies less to templates, since you often won't have a
separate declaration.)
--
James Kanze (GABI Software) email:james.kanze@gmail.com
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