generate和generate_n算法

generate和generate_n算法

分类： 数据结构与算法 C++ & API

算法目的用发生器对容器进行填充
template<typename ForwardIterator, typename Generator>
void   generate(ForwardIterator first, ForwardIterator last, Generator gen){
                for ( ; first != last; ++first)
                          *first = gen();
}
算法目的用发生器对容器从first开始进行填充n次
template<typename   OutputIterator, typename   Size, typename Generator>
OutputIterator   generate_n(OutputIterator first, Size n, Generator gen) {
                             for ( ; n > 0; --n, ++first)
                                   *first = gen();
                             return first;
}
当然为了使用这两个算法,你还要写一个发生器.随便举个例子:
struct Gen{
     int operator()(){
           return rand();//产生随机数的函数
     }
};

 

 boost例子

#include <list>
#include <algorithm>
#include <cstdlib>
#include <cassert>
#include <iostream>
#include "windows.h"
#include "time.h"
#include <boost/algorithm/minmax.hpp>
#include <boost/algorithm/minmax_element.hpp>

int main()
{
  using namespace std;

  // Demonstrating minmax()
  boost::tuple<int const&, int const&> result1 = boost::minmax(1, 0);
  assert( result1.get<0>() == 0 );
  assert( result1.get<1>() == 1 );

  // Demonstrating minmax_element()
  list<int> L;
  typedef list<int>::const_iterator iterator;
  srand(time(NULL));
  generate_n(front_inserter(L), 1000, rand);
  pair< iterator, iterator > result2 = boost::minmax_element(L.begin(), L.end());

  cout << "The smallest element is " << *(result2.first) << endl;
  cout << "The largest element is  " << *(result2.second) << endl;

  assert( result2.first  == std::min_element(L.begin(), L.end()) );
  assert( result2.second == std::max_element(L.begin(), L.end()) );
  Sleep(11111111);
}