Simply offer to insert and delete the list

In the insertion and deletion of the list must be careful not to let the list broken, in addition to pay special attention to the individual considerations of the enemy node

Reference Sword refers to the offer on page 50th Delete the code for the node of the given value. learned that to delete a node you must know the node's previous node. The code on the book uses Pnode.next and Pnode. Next.value to judge.

Here is the code attached, there is a question

 Public StaticListNode Deletenode (ListNode head,intvalue) {        if(head==NULL){            return NULL; } ListNode tobedelete=NULL; if(head.val==value) {Tobedelete=Head; }        Else{ListNode Phead=Head;  while(phead.next!=NULL&&phead.next.val!=value) {Phead=Phead.next; }            if(phead.next!=NULL&&phead.next.val==value) {Tobedelete=Phead.next; Phead.next=PHead.next.next; }        }        if(tobedelete!=NULL) {Tobedelete=NULL; }        returnHead; }

Simply offer to insert and delete the list