c++標準庫中有一個名為 std::remove函式，形式為

remove(beg,end,val)

remove_if(beg,end,unarryPred)

其中，beg，end為迭代器，也可以為指標

機理為：通過用儲存的元素覆蓋元素而從序列中“移去”元素。remove移去的元素為等於val值，remove_if移去的是當unarryPred為真的那些元素，然後返回一個迭代器，該迭代器指向未移去的最後一個元素的下一個位置。

我們需要注意的是，remove函式是通過覆蓋移去的，如果容器最後一個值剛好是需要刪除的，則它無法覆蓋掉容器中最後一個元素！我們來看下面一個例子，取自msdn

// remove.cpp
// compile with: /EHsc
// Illustrates how to use the remove function.
//
// Functions:
//   remove - remove all elements from the sequence that match value.
//   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.
//////////////////////////////////////////////////////////////////////

// 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, last;

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


    cout << "Before calling remove" << endl ;

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

    // remove all elements from Numbers that match 10
     last = remove(start, end, 10) ;

    cout << "After calling remove" << endl ;

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

    //print number of elements removed from Numbers
    cout << "Total number of elements removed from Numbers = "
        << end - last << endl ;

    //print only the valid elements of Number
    cout << "Valid elements of Numbers { " ;
    for(it = start; it != last; it++)
        cout << *it << " " ;
    cout << " }\n" << endl ;

}

Before calling remove
Numbers { 10 20 10 15 12 7 9 10  }

After calling remove
Numbers { 20 15 12 7 9 7 9 10  }    //我們可以看到，這邊最後一個元素

Total number of elements removed from Numbers = 3
Valid elements of Numbers { 20 15 12 7 9  }

第二個結果很有意思的，結果並不是20 15 12 7 9 9 9 10，從這裡我們也可以發現，remove實現機制是統一先找出哪些元素需要被覆蓋，等全部找到以後在進行一次性覆蓋，而不是每找到一個需要覆蓋的元素就將其進行覆蓋。因為我們知道，對於順序儲存的容器如vectro deque 來說，移動覆蓋代價是很大的，所以這麼做完全是從效能上來考慮的。