Java: binary tree recursion methods -

i'm quite new java , 1 of our assignments requires me create binary tree containing nodes int values. professor wants use 1 class containing main method. applied 2 recursive methods, 1 insert node , 1 display existing nodes. whenever run code however, console displays recent node entered. there wrong methods used? have far:

import java.util.scanner; public class node {  private int value; static node root; public node leftlink; public node rightlink;  public node(int v) {     this.value = v; }  public int getvalue() {     return value; }  static void traverseshow() {     if(root.leftlink != null){         root = root.leftlink;         traverseshow();     }     system.out.println(root.getvalue());     if(root.rightlink != null)     {         root = root.rightlink;         traverseshow();     }     return; }  static void addnode(node n) {     if(root==null)     {         root = n;     }     else     {            if(root.getvalue()>n.getvalue())         {             root = root.leftlink;             addnode(n);         }         if(root.getvalue()<n.getvalue())         {             root = root.rightlink;             addnode(n);         }     }     return; }  public static void main(string[] args)  {     int val = 0;     scanner sc = new scanner(system.in);     boolean loop = true;     string command = "";      while(loop==true)     {         system.out.println("please enter command:");         system.out.println("a = insert new value");         system.out.println("b = display values");         system.out.println("c = exit program");         command = sc.next();         if(command.equalsignorecase("a"))         {             system.out.println("enter value: ");             val = sc.nextint();             node newnode = new node(val);                addnode(newnode);         }         else if(command.equalsignorecase("b"))         {             traverseshow();         }         else if(command.equalsignorecase("c"))         {             sc.close();             system.exit(0);         }         else         {             system.out.println("invalid command! please try again.");         }     }    } } 

you're setting root new node when you're traversing tree find put new node. 1 simple option store current root in temporary variable , put after insert node.

static void addnode(node n) {     if(root==null)     {         root = n;     }     else     {         node tmp = root; // save current root         if(root.getvalue()>n.getvalue())         {             root = root.leftlink;             addnode(n);         }         else if(root.getvalue()<n.getvalue())         {             root = root.rightlink;             addnode(n);         }         root = tmp; // put root original value     }     return; } 

you should similar traverseshow method well.