gotour-notes/exercises/08-ebt/go.go

package main

import (
	"code.google.com/p/go-tour/tree"
	"fmt"
)

// Walk walks the tree t sending all values
// from the tree to the channel ch.
func Walk(t *tree.Tree, ch chan int) {
	// do it as a nested closure so that I can control the call to close so 
	// that I can use the range-based forloop in main.main
	var walk func(t *tree.Tree)
	walk = func(t *tree.Tree) {
		if t != nil {
			walk(t.Left)
			ch <- t.Value
			walk(t.Right)
		}
	}
	walk(t)
	close(ch)
}

// Same determines whether the trees
// t1 and t2 contain the same values.
func Same(t1, t2 *tree.Tree) bool {
	ch1 := make(chan int)
	ch2 := make(chan int)
	go Walk(t1, ch1)
	go Walk(t2, ch2)
	for i := range ch1 {
		if i != <-ch2 {
			return false
		}
	}
	return true
}

func main() {
	t := tree.New(1)
	ch := make(chan int)
	go Walk(t, ch)
	for i := range ch {
		fmt.Printf("%d, ", i)
	}
	fmt.Println()
	fmt.Println(Same(tree.New(1), tree.New(1)))
	fmt.Println(Same(tree.New(1), tree.New(2)))
}