Question
I have the following program and I have the necessary programs opened, but I keep getting this error when I compile it Error: LinkedList is not abstract and does not override abstract method iterator() in java.lang.Iterable How do I fix it? /** A linked list. */ public class LinkedList implements List, Predecessor { /** The first node in the List. */ private ListNode front; /** A LinkedList is initially empty. */ public LinkedList() { front = null; } public void add(Integer target) { if (isEmpty()){ front = new ListNode(target); } else { ListNode last = front; while (last.getNext() != null) { last = last.getNext(); } last.setNext(new ListNode(target)); } } public boolean contains(Integer target) { for (ListNode node = front; node != null; node = node.getNext()) { if (node.getItem().equals(target)) { return true; } } return false; } public Integer get(int index) { ListNode node = front; for (int i = 0; i < index; i++) { node = node.getNext(); } return node.getItem(); } public ListNode getNext() { return front; } public boolean isEmpty() { return front == null; } public Integer remove(int index) { Predecessor prev = this; ListNode node = front; for (int i = 0; i < index; i++) { prev = node; node = node.getNext(); } prev.setNext(node.getNext()); return node.getItem(); } public boolean remove(Integer target) { Predecessor prev = this; ListNode node = front; while (node != null) { if (node.getItem().equals(target)) { prev.setNext(node.getNext()); return true; } prev = node; node = node.getNext(); } return false; } public void set(int index, Integer target) { ListNode node = front; for (int i = 0; i < index; i++) { node = node.getNext(); } node.setItem(target); } public void setNext(ListNode next) { front = next; } public int size() { int tally = 0; for (ListNode node = front; node != null; node = node.getNext()) { tally++; } return tally; } public String toString() { String result = "( "; for (ListNode node = front; node != null; node = node.getNext()) { result += node.getItem() + " "; } return result + ")"; } }
Explanation / Answer
check this program now public class LinkedList implements List, Predecessor { private ListNode front; public LinkedList() { front = null; } public void add(Integer target) { if (isEmpty()) { front = new ListNode(target); } else { ListNode last = front; while (last.getNext() != null) { last = last.getNext(); } last.setNext(new ListNode(target)); } } public boolean contains(Integer target) { for(ListNode node = front; node != null; node = node.getNext()) { if (node.getItem().equals(target)) { return true; } } return false; } public Integer get(int index) { ListNode node = front; for (int i = 0; i