tree.go

package main

import (
       "fmt"
       "errors"
)

type Node struct{
     value int
     left * Node
     right * Node
}

func TraverseTree(root Node) {
     if root.value != 0 {
     	TraverseTree(*root.left)
     	fmt.Println(root.value)
	TraverseTree(*root.right)}
     return
}

func MakeNode(value int) (Node) {
     node := Node{value: value,
     	    	 right: &Node{},
		 left:  &Node{}}
     return node
}

func AddNode(root Node, value int) (newNode Node, error error){
     alreadyPresentError := errors.New("Element already present")
     if root.value == 0 {
     	fmt.Println("Creating new Node of value: ", value)
     	newNode = MakeNode(value)
	error = nil
     } else if root.value == value {
       	newNode = root
        error = alreadyPresentError
     }else if value > root.value{ //going right
     	fmt.Println("Going Right")
     	nodeLeft, err := AddNode(*root.right, value)
	if err != nil {
	    newNode = root
	    err = alreadyPresentError
	}else{
     	    newNode = Node{value: root.value, 
	       	           left:  root.left, 
		       	   right: &nodeLeft}
	    error = nil}
     }else if value < root.value{ //going left
        fmt.Println("Going left")
     	nodeRight, err := AddNode(*root.left, value)
	if err != nil {
	    newNode = root
	    err = alreadyPresentError
	}else{
     	    newNode = Node{value: root.value, 
	       	       left:  &nodeRight, 
		       right: root.right}
	    error = nil}}
     return
}