Re: how to specify overloaded function

From:
Mohammad Nabil Al-Aggan <mohammad.nabil.h@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Tue, 28 Jul 2009 21:29:32 -0700 (PDT)
Message-ID:
<ef4cd012-20de-41aa-99c8-83d00e4fbc42@k19g2000yqn.googlegroups.com>
On Jul 29, 6:45 am, "Amadeus W.M." <amadeu...@verizon.net> wrote:

I wan to do this:

#include <algorithm>

//
std::transform(Xj.begin(), Xj.end(), logXj.begin(), std::log);
//

where Xj and logXj are of type

class Foo
{
public:
        typedef double * iterator;
        typedef const double * const_iterator;

//

};

The compiler understandably gets confused by std::log, with the following
error:

fooMain.C:131: error: no matching function for call to =91transform(doubl=

e*,

double*, double*, <unresolved overloaded function type>)'
make: *** [main] Error 1

How do I specify that I want

double log(double) ?

Thanks!


Just add a cast to the overloaded type you desire:

#include <algorithm>
#include <vector>
#include <cmath>
#include <iostream>
using namespace std;
int main()
{
  vector<double> x;
  x.push_back(10);
  std::transform(x.begin(),x.end(),x.begin(),(double (*)(double))
std::log);
  cout << *x.begin();
}

// Prints: 2.30259

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