INFO: STL Sample for deque::erase and deque::clear Functions

ID: Q156590

The information in this article applies to:

The Standard C++ Library, used with:
- Microsoft Visual C++, 32-bit Editions, versions 4.2, 5.0, 6.0

SUMMARY

The sample code below illustrates how to use the deque::erase, deque::clear, deque::begin, and deque::end STL functions in Visual C++.

MORE INFORMATION

Required Header


   < deque>

Prototype


   iterator erase(iterator iter);
   iterator erase(iterator first, iterator last);
   void clear() const;

NOTE: The class/parameter names in the prototype may not match the version in the header file. Some have been modified to improve readability.

Description

The first erase member function removes the element of the container pointed to by iter. The second erase member function removes the elements of the container in the range [first, last). Both return an iterator that designates the first element remaining beyond any elements removed, or end() if no such element exists.

Removing N elements causes N destructor calls and an assignment for each of the elements between the insertion point and the nearer end of the sequence.

Removing an element at either end invalidates only iterators and references that designate the erased elements. Otherwise, erasing an element invalidates all iterators and references.

The clear member function calls erase( begin(), end()).

Sample Code


////////////////////////////////////////////////////////////////////// 
// 
// Compile options needed: -GX
// 
// deque.cpp :
// 
// Functions:
// 
//    erase
//    clear
//    begin
//    end
// 
// Written by Bobby Mattappally
// of Microsoft Product Support Services,
// Copyright (c) 1996 Microsoft Corporation. All rights reserved.
////////////////////////////////////////////////////////////////////// 

/* Compile options needed:-GX
*/ 
#include <iostream>
#include <deque>

#if _MSC_VER > 1020   // if VC++ version is > 4.2
   using namespace std;  // std c++ libs implemented in std
   #endif

typedef deque<int, allocator<int> >  INTDEQUE;

void print_contents (INTDEQUE  deque);

void main()

{

    // create a and with elements 1,2,3,4 and 5
    INTDEQUE  a;
    a.push_back(1);
    a.push_back(2);
    a.push_back(3);
    a.push_back(4);
    a.push_back(5);

    //print the contents
    print_contents (a);

    //  erase the second element
    a.erase(a.begin()+1);
    print_contents (a);

    //erase the last two elements
    a.erase(a.end()-2,a.end());
    print_contents (a);

    //clear a
    a.clear();
    print_contents (a);

}

void print_contents (INTDEQUE  deque) {
    INTDEQUE::iterator pdeque;

    cout <<"The output is: ";

        for(pdeque = deque.begin();
        pdeque != deque.end();
        pdeque++)
    {
        cout << *pdeque <<" " ;
    }
        cout<<endl;

}

Program Output is:


The output is: 1 2 3 4 5
The output is: 1 3 4 5
The output is: 1 3
The output is:

REFERENCES

Visual C++ Books On Line: Visual C++ Books:C/C++:Standard C++ Library Reference.

Additional query words: STL STLSample erase clear begin end

Keywords : kbcode kbVC420 kbVC500 kbVC600 kbDSupport STLIss
Version : winnt:4.2,5.0,6.0
Platform : winnt
Issue type : kbinfo