Re: Using <algorithm> with null-terminated arrays
On 2010-12-18 11:11:17 -0500, Virchanza said:
I want to use the std::sort function instead, but I see that you have
to supply a "one past the last valid element" iterator to it -- which
isn't cool when dealing with simple null-terminated arrays...
What do you think would be the most efficient way to do this using the
STL?
Define an iterator type that holds a pointer to the data, and define
its operator== to check whether the pointee is 0:
template <class Ty>
struct array_iterator
{
array_iterator() : ptr(0) {}
array_iterator(Ty *p) : ptr(p) {}
Ty *ptr;
};
template <class Ty> bool operator==(const array_iterator<Ty>& lhs,
const array_iterator<Ty>& rhs)
{
if (lhs.ptr == rhs.ptr)
return true;
else if (lhs.ptr == 0)
return *rhs.ptr == 0;
else if (rhs.ptr == 0)
return *lhs.ptr == 0;
else
return false;
}
The dance to make ptr private and still provide a templated friend
function is left as an exercise for the reader.
--
Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The
Standard C++ Library Extensions: a Tutorial and Reference
(www.petebecker.com/tr1book)
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