Java: pasar parámetros por valor o por referencia

Una explicación simple de los principios del paso de parámetros en Java.

Muchos programadores a menudo confunden qué parámetros en Java se pasan por valor y cuáles por referencia. Visualicemos este proceso, y luego verás lo simple que es todo.

Empecemos con lo básico.

Los datos se pasan entre métodos a través de parámetros. Hay dos formas de pasar parámetros:

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class Node {
   int data;
   Node next;
   Node(int d){
       data = d;
       next = null;
   }
}
class LinkedList {
   public static Node push(Node head, int data) {
       Node newNode = new Node(data);
       newNode.next = head;
       head = newNode;
       return head;
   }
   public static void deleteNode(Node head, int position) {
  
       // List is empty
       if (head == null){
           return;
       }

      // If position is 1st, removing head node
      if (position == 1) {
          head = head.next;
          return;
      }
      Node prevNode = head;
      int i = 2;
      while (prevNode != null && i != position) {
          prevNode = prevNode.next;
          i++;
      }
     // When position is more than number of node
     if (prevNode == null || prevNode.next == null) {
         return;
     }
     prevNode.next = prevNode.next.next;
   }
   public static void printList(Node head) {
       Node currNode = head;
       while (currNode != null) {
           System.out.print(currNode.data + " ");
           currNode = currNode.next;
       }
   }
   public static void main(String[] args) {
       Node head = null;
       head = push(head, 5);
       head = push(head, 4);
       head = push(head, 3);
       head = push(head, 2);
       head = push(head, 1);
       System.out.println("Created Linked list is: ");
       printList(head);

       // Delete node at position 2
       deleteNode(head, 2);

       System.out.println("\nLinked List after Deletion at position 2: ");
       printList(head);
   }
}

      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

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public static Node deleteNode(Node head, int position) {
   // List is empty
   if (head == null){
      return head;
   }

   // If position is 1st, removing head node
   if (position == 1) {
       head = head.next;
       return head;
   }
   Node prevNode = head;
   int i = 2;
   while (prevNode != null && i != position) {
       prevNode = prevNode.next;
       i++;
   }
   // When position is more than number of node
   if (prevNode == null || prevNode.next == null) {
       return head;
   }
   prevNode.next = prevNode.next.next;
   return head;
}
public static void main(String[] args) {
   Node head = null;
   head = push(head, 5);
   head = push(head, 4);
   head = push(head, 3);
   head = push(head, 2);
   head = push(head, 1);
   System.out.println("Created Linked list is: ");
   printList(head);

   // Delete node at position 2
   head = deleteNode(head, 2);

   System.out.println("\nLinked List after Deletion at position 2: ");
   printList(head);
}
//Rest of the code remains same

      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

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" Oracle Java Programmer (OCAJP)".

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