
Boost Users : 
From: Peter Dimov (pdimov_at_[hidden])
Date: 20050616 20:15:01
Elisha Berns wrote:
> Here is a short example, that of course doesn't do anything important:
>
> class X
> {
> public:
> X() {}
> ~X() {}
>
> std::vector< int > vecInteger;
>
> bool Sort(int const& lhs, int const& rhs)
> {
> return lhs < rhs;
> }
> };
>
> // then either outside the body of the class:
>
> X x;
>
> // or inside some other class method you want to sort the vector...
>
> // and here's the part that I don't see...
>
> std::sort(x.vecInteger.begin(); x.vecInteger.end(),
> boost::mem_fn(X::Sort));
mem_fn(&X::Sort) essentially creates the equivalent of the following
function:
bool mem_fn_sort( X * this_, int const & lhs, int const & rhs )
{
return this_>Sort( lhs, rhs );
}
Since X::Sort is a member function, it needs to operate on an object of type
X, which explains the additional argument.
std::sort needs a twoargument predicate, so assuming that you need to
invoke Sort on your original x, you should write
std::sort( x.vecInteger.begin(), x.vecInteger.end(),
boost::bind( &X::Sort, &x, _1, _2 )
);
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