std::not1 is an STL adapter to negate a predicate derived from std::unary_function. To negate a predicate derived from std::binary_function, use std::not2.

Example

Operating system: Ubuntu 10.04 LTS Lucid Lynx

IDE: Qt Creator 2.0.0

Project type: Qt4 Console Application

Compiler: G++ 4.4.1

Libraries used:

STL: from GCC, shipped with Qt Creator 2.0.0


#include <algorithm>

#include <cassert>

#include <functional>

#include <vector>



struct IsGood : std::unary_function<int,bool>

{

  bool operator() (const int x) const

  {

    return (x == 42);

  }

};



int main ()

{

  std::vector<int> v;

  for (int i=0; i!=100; ++i) { v.push_back(i); }

  //Count the good ones

  assert(std::count_if(v.begin(),v.end(),IsGood())==1);

  //Count the bad (not-good) ones

  assert(std::count_if(v.begin(),v.end(),std::not1(IsGood()))==99);

}

Download the C++ Qt Creator project of this example (zip)

External links

Cplusplus.com page about std::not1

Go back to Richel Bilderbeek's C++ page.

Go back to Richel Bilderbeek's homepage.

(C++) std::not1

Example

External links