La clase SplStack

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

Introducción

La clase SplStack proporciona la funcionalidad principal de una pila implementada mediante una lista doblemente enlazada estableciendo el modo iterador a SplDoublyLinkedList::IT_MODE_LIFO.

Sinopsis de la Clase

class SplStack extends SplDoublyLinkedList {
/* Constantaes heredadas constants */
/* Métodos heredados */
}

Ejemplos

Ejemplo #1 Ejemplo de SplStack

<?php
$q
= new SplStack();
$q[] = 1;
$q[] = 2;
$q[] = 3;
foreach (
$q as $elem) {
echo
$elem."\n";
}
?>

El resultado del ejemplo sería:

3
2
1

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User Contributed Notes 3 notes

up
39
lsroudi at gmail dot com
9 years ago
the SplStack is  simply a SplDoublyLinkedList with  an iteration mode IT_MODE_LIFO and IT_MODE_KEEP
up
7
lincoln dot du dot j at gmail dot com
5 years ago
<?php
//SplStack Mode is LIFO (Last In First Out)
 
$q = new SplStack();

$q[] = 1;
$q[] = 2;
$q[] = 3;
$q->push(4);
$q->add(4,5);

$q->rewind();
while(
$q->valid()){
    echo
$q->current(),"\n";
   
$q->next();
}
?>

Output
5
4
3
2
1
up
-9
daryledesilva at gmail dot com
3 years ago
<?php

// Exercise: Implement Queue using Stacks

class MyQueue {
    protected
$queue;
   
   
/**
     * Initialize your data structure here.
     */
   
function __construct() {
       
$this->queue = new \SplStack;
    }
 
   
/**
     * Push element x to the back of queue.
     * @param Integer $x
     * @return NULL
     */
   
function push($x) {
       
$this->queue->push($x);
    }
 
   
/**
     * Removes the element from in front of queue and returns that element.
     * @return Integer
     */
   
function pop() {
       
$length = count($this->queue);
       
$temp = [];
        while(!
$this->queue->isEmpty()){
           
$rv = $this->queue->pop();
            if(!
$this->queue->isEmpty()){
               
$temp[] = $rv;
            }
        }
        for(
$i = count($temp)-1; $i >= 0; $i--){
           
$this->queue->push($temp[$i]);  
        }
        return
$rv;
    }
 
   
/**
     * Get the front element.
     * @return Integer
     */
   
function peek() {
        return
$this->queue->bottom();
    }
 
   
/**
     * Returns whether the queue is empty.
     * @return Boolean
     */
   
function empty() {
        return
$this->queue->isEmpty();
    }
}

/**
* Your MyQueue object will be instantiated and called as such:
* $obj = MyQueue();
* $obj->push($x);
* $ret_2 = $obj->pop();
* $ret_3 = $obj->peek();
* $ret_4 = $obj->empty();
*/
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