Function object that prints the passed argument : Function object « STL Introduction « C++ Tutorial

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2. STL Introduction
3. Function object

/* The following code example is taken from the book        
 * "The C++ Standard Library - A Tutorial and Reference"
 * by Nicolai M. Josuttis, Addison-Wesley, 1999
 *
 * (C) Copyright Nicolai M. Josuttis 1999.
 * Permission to copy, use, modify, sell and distribute this software
 * is granted provided this copyright notice appears in all copies.
 * This software is provided "as is" without express or implied
 * warranty, and with no claim as to its suitability for any purpose.
 */
#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;

// simple function object that prints the passed argument
class PrintInt {
  public:
    void operator() (int elem) const {
        cout << elem << ' ';
    }
};

int main()
{
    vector<int> coll;

    // insert elements from 1 to 9
    for (int i=1; i<=9; ++i) {
        coll.push_back(i);
    }

    // print all elements
    for_each (coll.begin(), coll.end(),    // range
              PrintInt());                 // operation
    cout << endl;
}

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