fo/removeif1.cpp

The following code example is taken from the book
The C++ Standard Library - A Tutorial and Reference, 2nd Edition
by Nicolai M. Josuttis, Addison Wesley Longman, 2012
Copyright © 2012 by Pearson Education, Inc. and Nicolai M. Josuttis


#include <iostream>
#include <list>
#include <algorithm>
#include "print.hpp"
using namespace std;

class Nth {    // function object that returns true for the nth call
  private:
    int nth;       // call for which to return true
    int count;     // call counter
  public:
    Nth (int n) : nth(n), count(0) {
    }
    bool operator() (int) {
        return ++count == nth;
    }
};

int main()
{
    list<int> coll = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
    PRINT_ELEMENTS(coll,"coll:        ");

    // remove third element
    list<int>::iterator pos;
    pos = remove_if(coll.begin(),coll.end(),  // range
                    Nth(3));                  // remove criterion
    coll.erase(pos,coll.end());

    PRINT_ELEMENTS(coll,"3rd removed: ");
}