recursion - Java Binary tree insert is not working properly -

when add node example, named "bob" in insert method:

public void insert(string alabel){     //left recursion:     if(this.getlabel().compareto(alabel) <= 0) {         if (childrenleft == null) {             bstreenode anode = new  bstreenode(alabel,this);             return;         }     else {             childrenleft.insert(alabel);         }     }     //right recursion     else {         if (childrenright==null) {             bstreenode anode = new bstreenode(alabel,this);             return;         }     else{             childrenright.insert(alabel);         }      }  } 

my tree adds blank node no label on left side of treee only. there wrong (bstreenode anode = new bstreenode;)? because when hard code nodes like:

bstreenode louis = new bstreenode("louis", treeroot); bstreenode bonny = new bstreenode( "bonny", treeroot); bstreenode sue = new bstreenode("anne", bonny); bstreenode sam = new bstreenode("sam",louis); bstreenode anne2 = new bstreenode( "delta", bonny); bstreenode frank = new bstreenode("kalle", louis); 

the tree shows both label , inserted @ desired location. other code- constructor:

public bstreenode( string alabel,bstreenode aparent){     label = alabel;     parent = aparent;  //add node child of node's parent either left or right      if(parent != null){         if(parent.getlabel().compareto(label)<= 0) {             parent.addleftchild(this);         }         if(parent.getlabel().compareto(label)> 0) {             parent.addrightchild(this);         }      }  } 

this constructor adds node parent when node created. add childleft , right methods:

private void addleftchild(bstreenode anode){     if(childrenleft == null) this.childrenleft = anode;  } private void addrightchild(bstreenode anode) {     if(childrenright == null) this.childrenright = anode;  } 

most binary trees follow different style, , set parent's left/right child inside recursive method, instead of child going , telling it's new parent

this code bit more standard how binary trees function:

public void insert(string alabel) {     if(getlabel().compareto(alabel) <= 0)         if(childrenleft == null)             childrenleft = new bstreenode(alabel, this);         else             childrenleft.insert(alabel);     else         if(childrenright == null)             childrenright = new bstreenode(alabel, this);         else             childrenright.insert(alabel); } 

that code should correctly save values of bstreenodes being created, , has added effect of being less confusing how parent getting it's child

it makes whole lot more sense people parent getting child, instead of child reaching node , telling it's new child on block