Re: [Boost-users] [Bind] How do you write it?

27 Mar 2010


      On Tue, Mar 23, 2010 at 4:29 AM, Robert Jones  wrote:
...
Hi All
Ok, now I've found out what is really stopping my real code working.
In this example my problem is that method has defaulted arguements, which I
think mucks up bind's signature matching. Is there an easy way round this,
or
must I just add appropriate overloads of double_it to A?
Thanks, Rob.
#include <algorithm>
#include <vector>
#include "boost/bind.hpp"
struct A
{
    int double_it( int i, int j = 2 ) { return i * j; }
} 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 ) );
}
C++ type signatures do not see optional parameters, thus, pretend that
your function does not have a default value:

#include <algorithm>
#include <vector>
#include "boost/bind.hpp"

struct A
{
    int double_it( int i, int j = 2 ) { return i * j; }
} 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, 2 ) );
}

Re: [Boost-users] [Bind] How do you write it?

OvermindDL1