java - 有没有办法在程序完成后循环它？我总是遇到无限循环

Question

我制作了一个工资程序，我需要循环它，以便它为多个员工运行。

现在，它对一个人来说工作得很好，但如果我在程序顶部添加一个 while(true){ ，它会无限循环并永远打印消息。我对 Java 还很陌生，所以任何建议都会受到赞赏!

import java.util.*;
import java.text.*;

public class Wages {
    public static void main(String[] arg) {
        DecimalFormat money = new DecimalFormat("$0.00");
        int inTime = 0;
        int outTime = 0;
        int inMin = 0;//convert time to minutes for easier calculation
        int outMin = 0;
        int iLength = 0;
        double minWorked = 0;
        double hoursWorked = 0;
        double totalPay = 0;
        double PPH = 0; //pay per hour
        Scanner sc = new Scanner(System.in);
        String name = "";
        String timeIn = "";

        while (true) {
            while (iLength < 3) { //loop if input is invalid
                System.out.print("Please enter your name: ");
                name = sc.nextLine();
                name = name.trim(); //trim spaces
                iLength = name.length();//check length
                if (iLength < 3) {//error message
                    System.out.println("Please enter a name longer than 3 characters.");
                }
            }
            try {
                while ((inTime < 800 || outTime > 1900) || outTime <= inTime) {
                    System.out.print("Please enter your check in time: ");
                    inTime = sc.nextInt();
                    System.out.print("Please enter your check out time: ");
                    outTime = sc.nextInt();
                    if (inTime < 800 || outTime > 1900) {
                        System.out.println("Please enter work time between 800 and 1900.");
                    }
                    if (outTime <= inTime) {
                        System.out.println("Please enter a check out time later than your check in time.");
                    }
                }
                while (PPH < 7.75 || PPH > 15.20) {
                    System.out.print("Please enter your pay per hour: $");
                    PPH = sc.nextDouble();
                    if (PPH < 7.75 || PPH > 15.20) {
                        System.out.println("Please enter a pay between 7.75 and 15.20.");
                    }
                }
                inMin = (inTime / 100) * 60 + (inTime % 100);
                outMin = (outTime / 100) * 60 + (outTime % 100);
                minWorked = outMin - inMin;
                hoursWorked = minWorked / 60;
                totalPay = hoursWorked * PPH;
                System.out.println("\nEmployee Name: " + name);
                System.out.println("Check in time: " + inTime);
                System.out.println("Check out time: " + outTime);
                System.out.println("Hours worked: " + hoursWorked);
                System.out.println("Pay per hour: " + money.format(PPH));
                System.out.println("Total pay: " + money.format(totalPay));
            }//try
            catch (InputMismatchException ime) {
                System.out.println("Please enter time and pay as numbers.");
            }
        }//while(true)
    }//main
}//class

Answer 1

您永远不会重置输入变量。因此，当循环回到开始时，变量已经设置并且程序会跳过验证检查。

例如，在循环开始时我们设置 iLength和name 。说name="Alex"因此iLength=4 。这通过了while(iLength<3)查看。然后输入其余数据(让我们假装)并完成循环。然后我们回到代码while(iLength<3) 。因为我们还没有重置iLength , iLength仍然是 4，因此它甚至从不询问名称。

您需要在 while(true) 中声明变量循环，这意味着它们会在每个循环中被销毁并重新创建，或者您需要在每个循环结束时重置它们。例如: iLength=0;
name="";

还值得注意的是，您应该有办法打破无限循环。例如:

if (name.equalsIgnoreCase("exit")) return;

如果输入名称“exit”(无论大小写变化)，这将结束程序。