Check if element of linked list exists

Question

I am trying to determine if the value is a member in the link. if it is a member, it will return true otherwise it returns false. I try to do this

public boolean member(Integer val){
    if(node.val.equals(val) || node.next.val.equals(val)){
        System.out.println("true");
        return true;
    }
    return false;
}

However, it only check the value of the head and value of the next of the head. What would be other way to check the value of all node?

Solution 1

Just pass the root node and loop through your linkedList:

public boolean member(Node root, Integer val){
    Node currentNode = root;//keep track of current node
    while(currentNode != null){
        //switched currentNode.val and val to avoid null pointer exceptions
        if(val.equals(currentNode.val)){
        //if you're looking for nulls...still with the original
        //if(currentNode.val.equals(val)){
            System.out.println("true");
            return true;
        }
        currentNode = currentNode.next();//update current node
    }
    return false;
}

Solution 2

Ok without recursion:

public boolean member(Integer val){
  Node current = node;
  while (current != null) {
    if (current.val.equals(val)) {
      return true;
    } else {
      current = current.next;
    }
  }
  return false;
}

Solution 3

This solution uses a Boolean function to determine if element exists in linked list.

    public boolean doesValExist(int value){
    Node traveler = head;
    while(traveler != null){
        if(traveler.getElement() == value){
            return true;
        }
        traveler = traveler.getNext();
    }
    return false;
}