CODEWITHSUNDEEP
javaalgorithmlistsearchlinked-list
UserFuser
UserFuser

Reputation: 110

Why does this code go into a infinite loop?

I have wrote this code, which will do a search for chars in a linkedlist(called ListNode), checking if there are any chars which is in uppercase, and then storing them in a new linkedlist(and then return the new linkedlist). When I do run this code, it goes in a "infinite" loop not returning anything. Why is that? The NodeList does contain some uppercase chars. Here is the code:

public static ListNode copyUpperCase(ListNode head) {
    ListNode newListNode = mkEmpty();
    if(head == null){
        throw new ListsException("");
    }else{      
        while(head.next != null){
            if(Character.isUpperCase(head.element)){
                newListNode.element = head.element;         
                head = head.next;
            }
        }
    }
    return newListNode;
}

Upvotes: 1

Views: 73

Answers (1)

rgettman
rgettman

Reputation: 178333

What if the head.element character isn't uppercase? The head is never updated to head.next.

Place head = head.next; after your if block, so it's always executed.

Upvotes: 5

Related Questions