phdscholar80@yahoo.com wrote:
I am using the following code:
#include <vector>
#include <algorithm>
class A
{
};
bool comparator( A * b, const char * a )
{
// return appropriate true/false value
}
int main( int argc, char * argv[] )
{
std::vector< A * > vt;
const char * p = "a";
std::lower_bound( vt.begin(), vt.end(), p, comparator );
return 0;
}
Note that the second argument of the comparator function is the same
as 'p', the 'object' that is being provided. Is this a standard
compliant technique? If not, shouldn't the standard allow this? It
comes in useful in a LOT of situations. (Incase you are wondering,
this worked perfectly on Visual Studio 2003 but doesn't work on Visual
Studio 2005 with SP1).
I couldn't find any direct set of requirements for the 'Compare' argument
of 'lower_bound' template except that the container "should be partitioned
with respect to 'comp(e, value)'", where 'comp' is your 'comparator'.
Whether this requires the 'comparator' to be callable with 'a' and 'b'
reversed (that's what Visual C++ requires, and that's why it fails) is
open to interpretation.