java在尝试失败后关闭

Question

我试图有一个输入，要求我选择一个数字1-99，我也想有这个系统。在两次尝试失败后关闭（0），如果有人能帮助我，将不胜感激

package joey;

import java.util.Scanner;

public class Joey {

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        while (true)   { 
            System.out.println("Please enter an number between 0-99: ");
            int n = input.nextInt();
            if ((n > 99) || (n < 1))
                System.out.println("Invalid number");
            else
                break;          
       }
    }
}

Answer 1

对失败的尝试使用计数器（代码更新）：

import java.util.Scanner;
class Main {
    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        int failed = 0;

        while (failed < 2) {
            System.out.println("Please enter an number between 0-99: ");
            int n = input.nextInt();
            if ((n > 99) || (n < 1)) {
                System.out.println("Invalid number");
                failed += 1;
            } else {
                System.out.println("Correct! Closing now");
                return;
            }
        }        
        System.out.println("Finished after two failed attempts");
    }
}

看到了吗here

Answer 2

您需要创建一个标志变量。。。比如：

int counter = 0;

然后将while (true) {循环更改为：

do {
    //Do whatever you want here
    counter++; //Don't forget to increase the counter or you'll end up with an infinite loop
    //If number is in range 1-99 then incorrect = false otherwise it becomes true
} while (counter < 2 && incorrect);

if (incorrect) {
    System.out.println("Good bye! You failed!");
} else {
    System.out.println("Good bye! You approved!");
}

不需要System.exit(0);呼叫

或者你可以使用一个do-while循环，但我将由你决定

Answer 3

为了拥有“这个”系统。关闭时，只需手动完成程序运行，即退出循环。A.查一下你的电话号码。B.设置一个布尔标志，并使while循环在该标志上。当它改变状态时，循环将结束，计算机将返回到它的状态