打破我的循环

Question

我已经为程序创建了基本结构，但无论我尝试什么，我似乎都无法退出循环。

此外，我希望它显示用户将输入的信息;一旦我退出循环，从键盘到控制台，但我不知道如何做到这一点。

import java.util.Scanner;

public class Requirement1 {

    public static void main(String[] args) {

        Scanner scan = new Scanner (System.in);
        String name, game, time, points;
        int i = 0;

        System.out.println("Please Enter Your Name");
        name = scan.nextLine();
        System.out.println("Players Name: " + name);
        while (i < 100)
        {

        Scanner scan2 = new Scanner(System.in);
        System.out.println("Please Enter a Game Name (If You Are Done type \"quit\")");
        game = scan.nextLine();
        System.out.println("Game: " + game);

        Scanner scan3 = new Scanner (System.in);
        System.out.println("Please Enter Your Score");
        points = scan.nextLine();
        System.out.println("Your Score: " + points);

        Scanner scan4= new Scanner (System.in);
        System.out.println("Please Enter the amount of time Spent Playing in Minutes");
        time = scan.nextLine();
        System.out.println("Time played: " + time);
        }



    }

Answer 1

在循环内包含i++。

Answer 2

为了摆脱while循环，您需要使func renderNodeHieararchyForNode(node:SKNode, index:Int) { var i = 0 var beginning = "" while i != index { beginning += " " i++ if i == index { beginning += " " } } print("\(beginning)Node of type \(node.dynamicType) \(node.name != nil ? "('\(node.name!)')" : "") has zPosition = \(node.zPosition)\(node.children.count > 0 ? " and has children :" : ".")") for (i,child) in node.children.enumerate() { renderNodeHieararchyForNode(child, index: index+1) if i == node.children.count-1 { print("") } } } func renderNodeHiearchyForNode(node:SKNode) { renderNodeHieararchyForNode(node, index: 0) } 为false，或者添加一个显式语句来停止循环（i < 100，break，{{1 }或return，具体取决于您的要求。）

如果您想在用户输入throw并在循环后执行代码时中断循环：

System.exit

目前，"quit"永远不会从0更改，因此System.out.println("Please Enter a Game Name (If You Are Done type \"quit\")"); game = scan.nextLine(); if (game.equals("quit")) { break; } 始终为真。此外，它不会被读取。除非您出于其他目的需要它，否则可以删除i并将while循环声明更改为：

i < 100

这种情况显然永远不会是假的，所以你需要在循环中显式中断。

Answer 3

另一种方法是使用$user->{'mobilephone'} = $userDat['mobilephone']; 循环，更符合您的需求：

//code to initiate the object ImageView...
ImageView myImage = (ImageView) findViewById(R.id.pic);//pic is the id of ImageView in my xml file...

                    try 
                    {
                        // now, get the input stream
                        InputStream input= getAssets().open(c.getString(c.getColumnIndex("image")));//image is the name of field in my db which holds the path (ex. rice.jpg)...
                        // initiate image as drawable
                        Drawable draw = Drawable.createFromStream(input, null);
                        // set image to ImageView
                        myImage.setImageDrawable(draw);
                    }

                    catch(IOException ex) 
                    {
                        return;
                    }

Answer 4

一般来说，当我知道循环运行的确切次数时，我喜欢使用for循环。如果我不知道循环运行了多少次，那么我想使用while循环。

for循环：

import java.util.Scanner;

public class Requirement1 {

    public static void main(String[] args) {

        Scanner scan = new Scanner (System.in);
        String name, game, time, points;

        System.out.println("Please Enter Your Name");
        name = scan.nextLine();
        System.out.println("Players Name: " + name);

        for (int i = 0; i < 100; i++) {

            Scanner scan2 = new Scanner(System.in);
            System.out.println("Please Enter a Game Name (If You Are Done type \"quit\")");
            game = scan.nextLine();

            if (game.equals("quit")) {
                break;
            }
            System.out.println("Game: " + game);

            Scanner scan3 = new Scanner (System.in);
            System.out.println("Please Enter Your Score");
            points = scan.nextLine();
            System.out.println("Your Score: " + points);

            Scanner scan4= new Scanner (System.in);
            System.out.println("Please Enter the amount of time Spent Playing in Minutes");
            time = scan.nextLine();
            System.out.println("Time played: " + time);
        }
    }

while循环：

import java.util.Scanner;

public class Requirement1 {

    public static void main(String[] args) {

        Scanner scan = new Scanner (System.in);
        String name, game, time, points;

        System.out.println("Please Enter Your Name");
        name = scan.nextLine();
        System.out.println("Players Name: " + name);

        while (true) {

            Scanner scan2 = new Scanner(System.in);
            System.out.println("Please Enter a Game Name (If You Are Done type \"quit\")");
            game = scan.nextLine();

            if (game.equals("quit")) {
                break;
            }
            System.out.println("Game: " + game);

            Scanner scan3 = new Scanner (System.in);
            System.out.println("Please Enter Your Score");
            points = scan.nextLine();
            System.out.println("Your Score: " + points);

            Scanner scan4= new Scanner (System.in);
            System.out.println("Please Enter the amount of time Spent Playing in Minutes");
            time = scan.nextLine();
            System.out.println("Time played: " + time);
        }
    }

Answer 5

你的循环是一个简单的计数器，你可能想用for循环替换它，因为它表明循环不会因为循环中发生的某些操作而破坏：

for(int i = 0 ; i < 100 ; i++) {
    // block running 100 times
}

Answer 6

如果可能，请避免使用do / while支持for循环。如果游戏循环应在用户键入quit时结束，请添加break语句。

for (i = 0; i < 100; i++) {

    // get user's game choice from console

    if (game.equals("quit")){
        break;
    }

    // if they didn't type quit ...
}