Added go for Animal

00_Alternate_Languages/03_Animal/go/main.go

@@ -0,0 +1,159 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strings"
+)
+
+type node struct {
+	text    string
+	yesNode *node
+	noNode  *node
+}
+
+func newNode(text string, yes_node, no_node *node) *node {
+	n := node{text: text}
+	if yes_node != nil {
+		n.yesNode = yes_node
+	}
+	if no_node != nil {
+		n.noNode = no_node
+	}
+	return &n
+}
+
+func (n *node) update(newQuestion, newAnswer, newAnimal string) {
+	oldAnimal := n.text
+
+	n.text = newQuestion
+
+	if newAnswer == "y" {
+		n.yesNode = newNode(newAnimal, nil, nil)
+		n.noNode = newNode(oldAnimal, nil, nil)
+	} else {
+		n.yesNode = newNode(oldAnimal, nil, nil)
+		n.noNode = newNode(newAnimal, nil, nil)
+	}
+}
+
+func (n *node) isLeaf() bool {
+	return (n.yesNode == nil) && (n.noNode == nil)
+}
+
+func listKnownAnimals(root *node) {
+	if root == nil {
+		return
+	}
+
+	if root.isLeaf() {
+		fmt.Printf("%s           ", root.text)
+		return
+	}
+
+	if root.yesNode != nil {
+		listKnownAnimals(root.yesNode)
+	}
+
+	if root.noNode != nil {
+		listKnownAnimals(root.noNode)
+	}
+}
+
+func parseInput(message string, checkList bool, rootNode *node) string {
+	scanner := bufio.NewScanner(os.Stdin)
+	token := ""
+
+	for {
+		fmt.Println(message)
+		scanner.Scan()
+		inp := strings.ToLower(scanner.Text())
+
+		if checkList && inp == "list" {
+			fmt.Println("Animals I already know are:")
+			listKnownAnimals(rootNode)
+			fmt.Println()
+		}
+
+		if len(inp) > 0 {
+			token = inp
+		} else {
+			token = ""
+		}
+
+		if token == "y" || token == "n" {
+			break
+		}
+	}
+	return token
+}
+
+func avoidVoidInput(message string) string {
+	scanner := bufio.NewScanner(os.Stdin)
+	answer := ""
+	for {
+		fmt.Println(message)
+		scanner.Scan()
+		answer = scanner.Text()
+
+		if answer != "" {
+			break
+		}
+	}
+	return answer
+}
+
+func printIntro() {
+	fmt.Println("                                Animal")
+	fmt.Println("               Creative Computing Morristown, New Jersey")
+	fmt.Println("\nPlay 'Guess the Animal'")
+	fmt.Println("Think of an animal and the computer will try to guess it")
+}
+
+func main() {
+	yesChild := newNode("Fish", nil, nil)
+	noChild := newNode("Bird", nil, nil)
+	rootNode := newNode("Does it swim?", yesChild, noChild)
+
+	printIntro()
+
+	keepPlaying := (parseInput("Are you thinking of an animal?", true, rootNode) == "y")
+
+	for keepPlaying {
+		keepAsking := true
+
+		actualNode := rootNode
+
+		for keepAsking {
+			if !actualNode.isLeaf() {
+				answer := parseInput(actualNode.text, false, nil)
+
+				if answer == "y" {
+					if actualNode.yesNode == nil {
+						log.Fatal("invalid node")
+					}
+					actualNode = actualNode.yesNode
+				} else {
+					if actualNode.noNode == nil {
+						log.Fatal("invalid node")
+					}
+					actualNode = actualNode.noNode
+				}
+			} else {
+				answer := parseInput(fmt.Sprintf("Is it a %s?", actualNode.text), false, nil)
+				if answer == "n" {
+					newAnimal := avoidVoidInput("The animal you were thinking of was a ?")
+					newQuestion := avoidVoidInput(fmt.Sprintf("Please type in a question that would distinguish a '%s' from a '%s':", newAnimal, actualNode.text))
+					newAnswer := parseInput(fmt.Sprintf("For a '%s' the answer would be", newAnimal), false, nil)
+					actualNode.update(newQuestion+"?", newAnswer, newAnimal)
+				} else {
+					fmt.Println("Why not try another animal?")
+				}
+				keepAsking = false
+			}
+		}
+		keepPlaying = (parseInput("Are you thinking of an animal?", true, rootNode) == "y")
+	}
+}