go run binary_tree.go

binary_tree.go

package main

import (
	"fmt"
)

type Tree struct {
	Value int
	Left, Right *Tree
}

func insert(t *Tree, v int) *Tree {
	if t == nil	{
		return &Tree{v, nil, nil}
	}

	if v < t.Value {
		t.Left = insert(t.Left, v)
		return t
	}
	t.Right = insert(t.Right, v)
	return t 
}


func (tree *Tree) PreOrderWalk() {
	if tree == nil {
		return	
	}

	fmt.Println("pre order walk:", tree.Value)
	tree.Left.PreOrderWalk()
	tree.Right.PreOrderWalk()
}

func (tree *Tree) InOrderWalk() {
	if tree == nil {
		return
	}

	tree.Left.InOrderWalk()
	fmt.Println("In order walk:", tree.Value)
	tree.Right.InOrderWalk()
}

func (tree *Tree) PostOrderWalk() {
	if tree == nil {
		return
	}

	tree.Left.PostOrderWalk()
	tree.Right.PostOrderWalk()
	fmt.Println("Post order walk:", tree.Value)
}

func main() {
	datas := []int{4,2,1,3,5,6}
	var tree *Tree 

	for _, v := range datas  {
		tree = insert(tree, v)
	}

	fmt.Println("PreOrderWalk:")
	tree.PreOrderWalk() // should 4,2,1,3,5,6

	fmt.Println("InOrderWalk:")
	tree.InOrderWalk() // should 1,2,3,4,5,6

	fmt.Println("PostOrderWalk:")
	tree.PostOrderWalk() // should 1,3,2,6,5,4
}