{"id":2259,"date":"2018-02-17T10:27:12","date_gmt":"2018-02-17T15:27:12","guid":{"rendered":"https:\/\/www.manualjava.net\/?p=2259"},"modified":"2018-02-17T23:53:13","modified_gmt":"2018-02-18T04:53:13","slug":"vector-y-stack","status":"publish","type":"post","link":"https:\/\/www.manualjava.net\/?p=2259","title":{"rendered":"Vector y Stack"},"content":{"rendered":"

\"\"<\/p>\n

Tanto Vector como Stack son colecciones hist\u00f3ricas para guardar objetos de cualquier tipo. Se puede colocar cualquier n\u00famero de objetos ya que se redimensionan autom\u00e1ticamente.\u00a0<\/span><\/p>\n

Vector<\/span><\/strong><\/h2>\n

El comportamiento de un vector se asemeja al de un arreglo, con la bondad de que no es necesario controlar su tama\u00f1o; autom\u00e1ticamente, si fuera necesario, aumenta su capacidad. A partir de Java 2 la clase Vector implementa la interfaz List para que forme parte de las colecciones de Java. Tamb\u00eden, la plataforma Java 5 permite establecer el tipo concreto de elemento que puede guardar una colecci\u00f3n, y en particular un vector, para as\u00ed realizar comprobaciones de tipo durante el proceso de compilaci\u00f3n. Por ejemplo, un vector de cadenas (String).<\/span><\/p>\n

\u00a0 \u00a0 \u00a0 Vector<String> vc = new Vector<String>();<\/span>
\n\u00a0 \u00a0 \u00a0 vc.addElement(\u00abLontananza\u00bb);<\/span>
\n\u00a0 \u00a0 \u00a0 vc.addElement(new Integer(12));\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0\/\/ error de compilaci\u00f3n<\/span><\/p>\n

Sin embargo, si la declaraci\u00f3n es la siguiente:<\/span><\/p>\n

\u00a0 \u00a0 \u00a0 Vector vc = new Vector();<\/span><\/p>\n

Se puede a\u00f1adir cualquier tipo de elemento, no hay comprobaci\u00f3n de tipo:<\/span><\/p>\n

\u00a0 \u00a0 \u00a0\u00a0 vc.addElement(\u00abLontananza\u00bb);<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0vc.addElement(new Integer(12));\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \/\/ correcto<\/span><\/p>\n

Stack<\/strong><\/span><\/h2>\n

La clase Stack hereda el comportamiento de un vector y adem\u00e1s define las operaciones del tipo abstracto Pila (\u00faltimo en entrar primero en salir). Todas las operaciones se realizan por un \u00fanico punto, el final (cabeza o top) de la pila. La declaraci\u00f3n de Stack es la siguiente:<\/span><\/p>\n

\u00a0 \u00a0 \u00a0 \u00a0public class Stack extends Vector{<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 . . . <\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0}<\/span><\/p>\n

Los m\u00e9todos definidos por la clase:<\/span><\/p>\n

\u00a0 \u00a0 \u00a0 \u00a0public Stack();\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0\/\/ Constructor, crea una pila vac\u00eda<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0public Object push(Object n);\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0\/\/ A\u00f1ade el elemento n, devuelve n<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0public Object pop();\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \/\/ Devuelve elemento cabeza y lo quita de la pila<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0public Object peek();\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \/\/ Devuelve elemento cabeza sin quitarlo de la pila<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0public boolean empty();\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \/\/ Devuelve true si la pila est\u00e1 vac\u00eda<\/span><\/p>\n

Los elementos que almacena una colecci\u00f3n stack son de tipo gen\u00e9rico (tipo Object), esto hace necesario realizar conversi\u00f3n de tipo cuando se extraen. La plataforma Java 5 permite parametrizar el tipo de los elementos que guarda el stack, de tal forma que el compilador verifica el tipo.<\/span><\/p>\n

Ejemplo<\/span><\/strong><\/h3>\n

Mediante una pila se analiza si una palabra o frase es pal\u00edndromo. Se lee la palabra del teclado y a la vez cada car\u00e1cter se guarda en una pila. Los elementos de la pila han de ser de tipo Character, por consiguiente su declaraci\u00f3n es: Stack<Character> pila<\/strong>.<\/span><\/p>\n

\u00a0 \u00a0 \u00a0 \u00a0import java.util.*;<\/span><\/p>\n

\u00a0 \u00a0 \u00a0 \u00a0public class Palindrome {<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 public static void main(String[] args) {<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0Scanner entrada = new Scanner(System.in);<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0Stack<Character> pila;<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0String palabra;<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0boolean palindrome;<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0pila = new Stack<Character>();<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0try{<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 System.out.print(\u00abIngresar palabra o frase: \u00ab);<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 while((palabra = entrada.nextLine()) != null){<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 for(int i=0;i<palabra.length();i++)<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0pila.push(new Character(palabra.charAt(i)));<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 palindrome=true;<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 int i=0;<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 while(palindrome && !pila.empty()){<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 Character q;<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 q = pila.pop();<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 palindrome = q.charValue() == palabra.charAt(i++);<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 }<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 if(palindrome && pila.empty())<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 System.out.println(palabra + \u00bb es un palindrome\u00bb);<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 else<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 System.out.println(palabra + \u00bb no es un palindrome\u00bb);<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 }<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0}catch(Exception e){};<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 }<\/span>
\n\u00a0 \u00a0 \u00a0 \u00a0}<\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

Tanto Vector como Stack son colecciones hist\u00f3ricas para guardar objetos de cualquier tipo. Se puede colocar cualquier n\u00famero de objetos ya que se redimensionan autom\u00e1ticamente.\u00a0<\/p>

Seguir leyendo<\/a><\/p>\n","protected":false},"author":1,"featured_media":2262,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[17],"tags":[],"_links":{"self":[{"href":"https:\/\/www.manualjava.net\/index.php?rest_route=\/wp\/v2\/posts\/2259"}],"collection":[{"href":"https:\/\/www.manualjava.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.manualjava.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.manualjava.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.manualjava.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2259"}],"version-history":[{"count":10,"href":"https:\/\/www.manualjava.net\/index.php?rest_route=\/wp\/v2\/posts\/2259\/revisions"}],"predecessor-version":[{"id":2272,"href":"https:\/\/www.manualjava.net\/index.php?rest_route=\/wp\/v2\/posts\/2259\/revisions\/2272"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.manualjava.net\/index.php?rest_route=\/wp\/v2\/media\/2262"}],"wp:attachment":[{"href":"https:\/\/www.manualjava.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2259"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.manualjava.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2259"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.manualjava.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2259"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}