Q156760: STL Sample for deque::front and deque::back Functions

Article: Q156760
Product(s): Microsoft C Compiler
Version(s): 4.2,5.0,6.0
Operating System(s): 
Keyword(s): kbcode kbVC420 kbVC500 kbVC600 kbDSupport
Last Modified: 26-MAR-2002

-------------------------------------------------------------------------------
The information in this article applies to:

- The Standard C++ Library, used with:
   - Microsoft Visual C++, 32-bit Enterprise Edition, versions 4.2, 5.0, 6.0 
   - Microsoft Visual C++, 32-bit Professional Edition, versions 4.2, 5.0, 6.0 
   - Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
   - Microsoft Visual C++.NET (2002) 
-------------------------------------------------------------------------------

SUMMARY
=======

The sample code below illustrates how to use the deque::front and deque::back
STL functions for the deque container class in Visual C++.

MORE INFORMATION
================

Required Header
---------------

     < deque>

Prototype
---------

     reference front();
     const_reference front() const;

     reference back();
     const_reference back() 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 member function front() returns a reference to the first element of the
controlled sequence, which must be non-empty.

The member function back() returns a reference to the last element of the
controlled sequence, which must be non-empty.

Sample Code
-----------

NOTE: In the first line of the sample code section, /GX is equivalent to /EHsc in
VC++ .NET and is set by default.

     ////////////////////////////////////////////////////////////////////// 
     // 
     // Compile options needed: -GX
     // 
     // deque.cpp :
     // 
     // Functions:
     // 
     //    front()
     // 
     //    back()
     // 
     // 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<char, allocator<char> >  CHARDEQUE;
     void print_contents (CHARDEQUE  deque, char*);

     void main()
     {
         //create a  with  A, B, C and D
         CHARDEQUE  a;
         a.push_back('A');
         a.push_back('B');
         a.push_back('C');
         a.push_back('D');

         //print out the contents
         print_contents (a,"a");

         cout <<"The first element of a is " <<a.front() <<endl;

         cout <<"The last element of a is " <<a.back() <<endl;

         //now let us modify the first and last elements
         //using reference ,front() and back()

         CHARDEQUE::reference reffront=a.front();
         CHARDEQUE::reference refback=a.back();

         reffront='X';
         refback='Y';

          //print out the contents
          print_contents (a,"a");

         }

     //function to print the contents of deque
     void print_contents (CHARDEQUE  deque, char *name)
     {
         CHARDEQUE::iterator pdeque;

         cout <<"The contents of "<< name <<" : ";

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

     }

Program output is:

  The contents of a : A B C D

  The first element of a is A

  The last element of a is D

  The contents of a : X B C Y

REFERENCES
==========

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

Additional query words: STL STLSample deque front back reference

======================================================================
Keywords          : kbcode kbVC420 kbVC500 kbVC600 kbDSupport 
Technology        : kbVCsearch kbAudDeveloper kbVCNET kbVCLibrary
Version           : :4.2,5.0,6.0
Issue type        : kbinfo

=============================================================================

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 1986-2002.