Question

我正在编写此程序来适应类型（不是对象！）。

基本前提是用户输入一个动物名称（牛，蛇鸟），然后输入一个动作（吃，移动，发声。）然后我的代码对其进行查找并返回值。

因此，假设用户输入位于由“”分隔的一行上。我使用strings.Split。

当用户仅输入一个字符时，我会收到“紧急”通知。我认为这种恐慌是由于编译器试图“拆分”单个字符而引起的。

两个问题： 1.我说的对吗？ 2.如何解决？

package main

import (
    "bufio"
    "fmt"
    "os"
    "strings"
)

//Create our type object.
type animal struct {
    aType, eats, moves, sounds string
}

//Create our methods.
func (animal animal) info (querie string) {
    if querie == "eats" {
        fmt.Printf("The animal, %s , eats %s\n ", animal.aType, animal.eats)
    } else if querie == "moves" {
        fmt.Printf("The animal, %s , moves by  %s\n ", animal.aType, animal.moves)
    } else {
        fmt.Printf("The animal, %s , makes the sound %s\n ", animal.aType, animal.sounds)
    }
}

func main() {
    //Now create our animals

    cow := animal{aType:"cow", eats: "grass", moves: "walking", sounds: "moo"}
    bird := animal{aType:"bird", eats: "worms", moves: "flying", sounds: "peep"}
    snake := animal{aType:"snake", eats: "mice", moves: "slithering", sounds: "hiss"}
    // need a boolean to perpetuate our loop
    var flag bool = true

    for flag {
        fmt.Println("Remember enter X to exit")
        fmt.Printf(">please enter your (format: type & information) request -> ")
        scanner := bufio.NewScanner(os.Stdin)
        scanner.Scan()
        request := scanner.Text()

        //Capture user entered data

        typed := strings.Split(request, " ")[0]
        if typed == "X" {
            flag = false
            break
        }
        infoe := strings.Split(request, " ")[1]

        // contruct the logic tree. 

        if !((infoe == "eat") || (infoe == "move") || (infoe == "speak")) {
            switch typed {
            case "cow": 
                cow.info(infoe)

            case "snake": 
                snake.info(infoe)

            case "bird": 
                bird.info(infoe)
            default: 
                fmt.Println("I don't know about that animal.")          
            }
        } else {
            fmt.Printf("I don't have that informtion")
                break
            }
        }
    }

Answer 1

在循环外部创建扫描程序，以避免丢弃缓冲的数据。当Scan（）返回false时中断。检查并处理无效的输入。

scanner := bufio.NewScanner(os.Stdin)
for {
    fmt.Println("Remember enter X to exit")
    if !scanner.Scan() {
        break
    }
    request := scanner.Text()
    parts := strings.Split(request, " ")
    if parts[0] == "X" {
        break
    }
    if len(parts) < 2 {
        fmt.Println("bad input")
        break
    }

    typed := parts[0]
    infoe := parts[1]

    ...

Answer 2

为简化代码，我建议如下使用void countDocuments() async { StreamSubscription<QuerySnapshot> _myDoc = await Firestore.instance.collection('users').snapshots().listen((result) { countDocument = result.documents.length; print(countDocument); });：

fmt.Scanf

也不确定为什么会有多个下注。代码编写方式是否有问题？我认为如果有人只是想学习这种语言就可以。首先使它工作，然后专注于其他事情。

一旦您熟悉了该语言，就可以遍历Effective Go

中列出的要点

我开始恐慌，索引超出范围，无法退出

2 个答案: