C++ Primer 学习中。。。

简单记录下我的学习过程 (代码为主)

//全部容器适用

nth_element(b,n,e)

nth_element(b,n,e,p)

对照：partition()算法

/**------http://blog.csdn.net/u010579068------**/

#include<iostream>

#include<cstdio>

#include<string>

#include<vector>

#include<list>

#include<functional>

#include<deque>

#include<algorithm>

using namespace std;

/*****************************************

//全部容器适用

nth_element(b,n,e)

nth_element(b,n,e,p)

对照：partition()算法

*****************************************/

/**----------------------------------------------------------------------------------

----------------------------------------------------------------------------------**/

/*************************************************************************************

std::nth_element                    全部排序容器适用                        algorithm

--------------------------------------------------------------------------------------

template <class RandomAccessIterator>

  void nth_element ( RandomAccessIterator first, RandomAccessIterator nth,

                     RandomAccessIterator last );

template <class RandomAccessIterator, class Compare>

  void nth_element ( RandomAccessIterator first, RandomAccessIterator nth,

                     RandomAccessIterator last, Compare comp );

//eg：

*************************************************************************************/

bool myfunction (int i,int j)

{

    return (i>j);

}

int main ()

{

    int m[]= {3,4,5,6,7,2,3,4,5,6,1,2,3,4,5};

    vector<int> myvector(m,m+15);

    vector<int>::iterator it;

//  set some values:

//    for (int i=1; i<10; i++) myvector.push_back(i);   // 1 2 3 4 5 6 7 8 9

//    random_shuffle (myvector.begin(), myvector.end());

    cout << "myvector contains:(原始数据)";

    for (it=myvector.begin(); it!=myvector.end(); ++it)

        cout << " " << *it;

    cout << endl;

//   using default comparison (operator <):

//   cout<<*(myvector.begin()+3)<<endl;

    nth_element (myvector.begin(), myvector.begin()+3, myvector.end());

    cout << "myvector contains:(从小到大)";

    for (it=myvector.begin(); it!=myvector.end(); ++it)

        cout << " " << *it;

    cout << endl;

//  using function as comp

//    cout<<*(myvector.end()-4)<<endl;

//    nth_element (myvector.begin(), myvector.begin()+3, myvector.end(),myfunction);

    nth_element (myvector.begin(), myvector.end()-4, myvector.end(),greater<int>());

    // print out content:

    cout << "myvector contains:(从大到小)";

    for (it=myvector.begin(); it!=myvector.end(); ++it)

        cout << " " << *it;

    cout << endl;

    return 0;

}