std::bind1st is deprecated [2]. The function template std::bind provides a better solution [2].
std::bind1st is a binder to call a binary function with the value bound as first argument. If the second argument needs to be bound, use std::bind2nd instead.
The use of std::bind1st is clearest in division:
- If on all elements, an element called x, you want to perform '1.0 / x', use std::bind1st one the 1.0. This is demonstrated in the function Reciprocal, which is shown below in the example
- If on all elements, an element called x, you want to perform 'x / 2.0', use std::bind2nd one the 2.0. This is demonstrated in the function Halve
Example: Reciprocal
Reciprocal replaces all elements by their reprocicals, that is replaces all elements called 'x' by '1.0/x'.
#include <algorithm> #include <numeric> #include <vector> //From http://www.richelbilderbeek.nl/CppReciprocal.htm void Reciprocal(std::vector<double>& v) { std::transform(v.begin(),v.end(),v.begin(), std::bind1st(std::divides<double>(),1.0)); }
- Prefer Lambda expressions over binders [1]
- Scott Meyers. C++ And Beyond 2012 session: 'Initial thoughts on Effective C++11'. 2012. 'Prefer Lambdas over Binders'
- Working Draft, Standard for Programming Language C++. 2014-08-22. N3936. Paragraph D.10. 'The binders binder1st, bind1st and bind2nd are deprecated [Note: the function template bind provides a better solution -end note]'