partition (STL Samples)

說明如何使用磁碟分割 Visual C++ 標準樣板程式庫 (STL) 函式。

template<class BidirectionalIterator, class Predicate> inline
   BidirectionalIterator partition(
      BidirectionalIterator First,
      BidirectionalIterator Last,
      Predicate Predicate
   )

備註

注意事項
在原型中的類別/參數名稱不相符的標頭檔中的版本。某些已修改以提高可讀性。

磁碟分割演算法來排列在範圍內的項目 [First， Last)，讓其項目Predicate傳回 ，則為 true 之前，哪一個述詞傳回的項目 ，則為 false。演算法會傳回位於第一個元素為其 iterator Predicate會傳回 ，則為 false。

範例

// partition.cpp
// compile with: /EHsc
// Illustrates how to use the partition function.
//
// Functions:
//   partition  - Partition a range using a predicate.
//
//   begin      - Returns an iterator that points to the first element
//                in a sequence.
//
//   end        - Returns an iterator that points one past the end of
//                a sequence.
//
//   bind2nd    - Returns true for elements for which the condition
//                is true.

// disable warning C4786: symbol greater than 255 character,
// okay to ignore
#pragma warning(disable: 4786)

#include <iostream>
#include <vector>
#include <algorithm>
#include <functional>

using namespace std;

int main()
{
    const int VECTOR_SIZE = 8 ;

    // Define a template class vector of integers
    typedef vector<int > IntVector ;

    //Define an iterator for template class vector of integer
    typedef IntVector::iterator IntVectorIt ;

    IntVector Numbers(VECTOR_SIZE) ;   //vector containing numbers

    IntVectorIt start, end, it ;

    start = Numbers.begin() ;   // location of first
                                // element of Numbers

    end = Numbers.end() ;       // one past the location
                                // last element of Numbers

    //Initialize vector Numbers
    Numbers[0] = 6 ;
    Numbers[1] = 20 ;
    Numbers[2] = 10 ;
    Numbers[3] = 15 ;
    Numbers[4] = 12 ;
    Numbers[5] = 7 ;
    Numbers[6] = 9 ;
    Numbers[7] = 10 ;

    cout << "Before calling partition" << endl ;

    // print content of Numbers
    cout << "Numbers { " ;
    for(it = start; it != end; it++)
        cout << *it << " " ;
    cout << " }\n" << endl ;

    // partition the sequence such that all the elements
    // less than 11 appear before all the elements greater than 11
    it =  partition(start, end, bind2nd(less<int>(), 11)) ;

    cout << "After calling partition" << endl ;

    // print content of Numbers
    cout << "Numbers { " ;
    for(it = start; it != end; it++)
        cout << *it << " " ;
    cout << " }\n" << endl ;

}

Output

Before calling partition
Numbers { 6 20 10 15 12 7 9 10  }

After calling partition
Numbers { 6 10 10 9 7 12 15 20  }

需求

標頭: <algorithm>

請參閱

概念

標準樣板程式庫範例