functor(function object)

#include <iostream>
#include <list>
#include <iterator>
#include <algorithm>
using namespace std;
template<typename type>
class Add{   
 private:
    type number;
 public:
    Add(type initv) : number(initv){}
    const type& operator()(type& elem) const
    {
        elem += number;
  return elem;
    }  
};

int main()
{
    list<int> coll;
    for(int i = 0; i < 20; ++i)
    {
  coll.push_front(i);
        coll.push_back(i);        
    }
    transform( coll.begin(), coll.end(),
               coll.begin(), Add<int>(10) );
    copy( coll.begin(), coll.end(),
      ostream_iterator<int>(cout, " "));  
    cout << endl;
 for_each(coll.begin(), coll.end(), Add<int>(2));
 copy( coll.begin(), coll.end(),
      ostream_iterator<int>(cout, " "));  
    cout << endl;
    cin.get();
    return 0;
} 

本文地址：http://com.8s8s.com/it/it26191.htm