Databases
StackOverflow2013
Postsdbo
POGet Method, Insert, and Remove At Methods For a Custom Linked List
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POGet Method, Insert, and Remove At Methods For a Custom Linked List
    primarykey
    data
    text
    <p>I am having a great deal of trouble trying to implement these three methods in a custom Linked List I am creating. The get(int pos) method will return null for everything but the 0th index even when I have an existing Linked List! My removeAt(int pos) and insert(int pos, int n) methods are having the same trouble. I'll include everything I believe is relevant.</p> <p><strong>My Node Class</strong></p> <pre><code> public class MyNode { public int cargo; public MyNode next; public MyNode() { cargo = 0; next = null; } public MyNode(int i) { cargo = i; next = null; } } </code></pre> <p><strong>My Custom Linked List</strong></p> <pre><code>public class MyLinkedList { MyNode head; int size; public MyLinkedList() { head = null; size = 0; } public int get(int pos) { MyNode current = new MyNode(); for(int i = 0; i &lt;= pos &amp;&amp; current != null; i++) { if(pos == 0){ current = head; }else{ current = current.next; break; } } return current.cargo; } public void insert(int pos, int n) { MyNode current = new MyNode(n); MyNode before = new MyNode(get(pos-1)); if(before.next != null) { before.next = current.next; } else { before.next = current; } size++; System.out.println("Inserted " + n + " at position " + pos); } public void removeAt(int pos) { MyNode before = new MyNode(get(pos -1)); MyNode remove = new MyNode(get(pos)); MyNode after = null; int cargo = remove.cargo; if(remove.next != null) { after = remove.next; } before.next = after; size--; System.out.println("Removed " + cargo + " from position " + pos); } } </code></pre> <p><strong>My Test Data</strong></p> <pre><code>l.add(17); l.add(14); l.add(43); l.add(50); System.out.println(l.get(1)); </code></pre> <p>returns a NullPointer Exception at the sysout</p>
    singulars
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PTQuestion
    1. This table or related slice is empty.
    1. USuser1861162
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POGet Method, Insert, and Remove At Methods For a Custom Linked List
      1. This table or related slice is empty.
      1. VTDownMod
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload