DOCUMENT:Q157622  02-MAY-2002  [visualc]
TITLE   :STL Sample for queue::(push,pop,empty,back,front) Functions
PRODUCT :Microsoft C Compiler
PROD/VER::4.2,5.0,6.0
OPER/SYS:
KEYWORDS:kbcode kbtemplate kbSTL kbVC420 kbVC500 kbVC600 kbDSupport

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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) 
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NOTE: Microsoft Visual C++ NET (2002) supported both the managed code model that is provided by the .NET Framework and the unmanaged native Windows code model. The information in this article applies to unmanaged Visual C++ code only.

SUMMARY
=======

The sample code below illustrates how to use the queue::push, queue::pop,
queue::empty, queue::back, queue::front, and queue::size STL functions in Visual
C++.

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

The queue adapter holds objects of the type defined by the type of container
supported by the queue. The two containers supported are the list and the deque.
Objects are inserted by push() and removed by pop(). front() returns the oldest
item in the queue (also known as FIFO), and back() returns the latest item
inserted in the queue.

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

      <queue>

Prototypes
----------

   queue::push();
   queue::pop();
   queue::empty();
   queue::back();
   queue::front();
   queue::size();

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

Description
-----------

The sample shows queue implementation using list and deque containers.

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

   ////////////////////////////////////////////////////////////////////// 
   // 
   // Compile options needed: none
   // 
   // <filename> :  queue.cpp
   // 
   // Functions:
   // 
   //    queue::push(), queue::pop(), queue::empty(), queue::back(),
   //    queue::front(),queue::size()
   // 
   // Written by Debabrata Sarma
   // of Microsoft Product Support Services,
   // Copyright (c) 1996 Microsoft Corporation. All rights reserved.
   ////////////////////////////////////////////////////////////////////// 

   /* Compile options needed: /GX
   */ 
   #include <list>
   #include <iostream>
   #include <queue>
   #include <deque>
   using namespace std;

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

   // Using queue with list

   typedef list<int, allocator<int> > INTLIST;
   typedef queue<int,INTLIST >  INTQUEUE;

   // Using queue with deque

   typedef deque<char*, allocator<char*> > CHARDEQUE;
   typedef queue<char*,CHARDEQUE> CHARQUEUE;

   void main(void)

   {

       int size_q;
       INTQUEUE q;
       CHARQUEUE p;

       // Insert items in the queue(uses list)
       q.push(42);
       q.push(100);
       q.push(49);
       q.push(201);

       // Output the item inserted last using back()
       cout << q.back() << endl;

       // Output the size of queue
       size_q = q.size();
       cout << "size of q is:" << size_q << endl;

       // Output items in queue using front()
       // and use pop() to get to next item until
       // queue is empty
       while (!q.empty())
       {
           cout << q.front() << endl;
           q.pop();

       }

   // Insert items in the queue(uses deque)
       p.push("cat");
       p.push("ape");
       p.push("dog");
       p.push("mouse");
       p.push("horse");

       // Output the item inserted last using back()
       cout << p.back() << endl;

       // Output the size of queue
       size_q = p.size();
       cout << "size of p is:" << size_q << endl;

       // Output items in queue using front()
       // and use pop() to get to next item until
       // queue is empty
       while (!p.empty())
       {
           cout << p.front() << endl;
           p.pop();

       }

   } 

Program Output:

201
size of q is:4
42
100
49
201
horse
size of p is:5
cat
ape
dog
mouse
horse

REFERENCES
==========

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

Additional query words: STL STLSample push pop empty back front size

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

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