STL Sample for queue::(push,pop,empty,back,front) Functions

• The Standard C++ Library included with: - Microsoft Visual C++, 32-bit Edition, version 4.2

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>

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

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:none
*/
#include <list>
#include <iostream>
#include <queue>
#include <deque>

// Using queue with list

// Using queue with deque

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.