Re: [Boost-users] [Bind] Is this how to write it?

23 Mar 2010

      On Tue, Mar 23, 2010 at 9:49 AM, Robert Jones  wrote:
...
Hi All
In this bit of code....
#include <algorithm>
#include <vector>
#include "boost/bind.hpp"
struct A
{
    int double_it( int i ) { return i * 2; }
} a;
std::vector< int > v;
int main( )
{
    for ( std::vector< int >::iterator i = v.begin( ); i != v.end( ); ++ i )
    {
        a.double_it( * i );
    }
    // Write it as a for_each/bind
    std::for_each( v.begin(), v.end(), boost::bind( & A::double_it, boost::ref( a ), _1 ) );
}
Is that last line the idiomatic way of writing the bind expression?
Thanks, Rob.
Your code is fine when the bound thing is a method - you could use
'&a' rather than 'boost::ref(a)' (a pointer to 'a' can be used for a
method call in place of a reference to 'a')

However, for your 'double_it', I'd personally just write a function
rather than define a struct with a method. Then, 'a' is not needed and
the bind would be:

std::for_each( v.begin(), v.end(), boost::bind( &double_it, _1 ) );

HTH!

Stuart Dootson