有没有办法在程序结束时循环我的程序？我总是得到一个无限循环

Question

我制定了工资计划，我需要将其循环，以便为多名员工运行。

现在，它适用于一个人，但如果我在程序的顶部粘贴while(true){，它会无限循环并永久打印消息。我对Java很陌生，所以任何建议都值得赞赏！

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，当循环返回到开始时，变量已经设置，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"，然后iLength=4。这会通过while(iLength<3)检查。然后输入其余数据（让我们假装）并完成循环。然后我们回到代码段while(iLength<3)。由于我们尚未重置iLength，iLength仍为4，因此它甚至不会要求提供名称。

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

值得注意的是，你应该有办法打破无限循环。 EG：

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

如果输入名称“exit”（任何案例变化），这将结束程序。

Answer 2

您还可以使用for(;;) {}创建一个无限循环，然后根据条件（运行次数/用户输入/等）创建break。

Answer 3

如果您知道有多少员工，那么请使用for循环。

如果您不知道有多少员工，那么您需要询问用户何时退出并在while循环中使用该答案，例如：

boolean goAgain = true;
while(goAgain){
    //do your employee stuff
    //ask user if they want to go again
    goAgain = false; //assuming the user is finished
}

Answer 4

这是以前所有答案的组合。可能需要一些边缘案例测试，但重置变量从一开始就重新开始工资。 do while只是我的偏好。

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 = "";
  boolean again = true;
do{
      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));  
             System.out.println("Do you want to enter another employee? (Y/N)");
             if (sc.next().equalsIgnoreCase("n")){//left the exception handling up to you 
                 again = false;  
             }
             iLength =0;
             inTime = 0;
             outTime= 0;
             PPH = 0;
        }
      catch(InputMismatchException ime){
         System.out.println("Please enter time and pay as numbers.");
        }
    }while(again);
}