Java方法，先显示欢迎消息，然后显示“谢谢”消息

Question

The whole code is pretty simple, from a previous project we more or less convert it to make use of methods. Basically it prompts the user for their name, hours worked, and pay rate, takes that info and calculates it for the net pay. I've written up the majority of the code and from my understanding it works fine.

Now to my question. One method must print a message to the screen, I have to call the method once, at the beginning of the program, to print a welcome message and once, at the end of the program to print the Thank you message. With that, I am lost on how to make it so a single method can determine when it is the end of the program. (When the user enters a -1 when prompted to enter their name, the program will end.)

package project.pkg2;

import java.util.*;

public class Project2 {

// Scanner for the console inputs
static Scanner console = new Scanner (System.in);

public static void main(String[] args) {

    String name, formatNet;
    double hours, pay, netPay;

 // Prints the welcome message from the method.
    welcomeMessage();

 // Every initialized variable receives the return statements from their respected methods.        
    name  = getName();

    while (!(name.equals("-1")))
    {
    pay   = getPay ();
    hours = getHours ();
    netPay = calcNet(pay,hours);

 // Formats the net pay to be 2 decimals.   
    formatNet = String.format("%.2f", netPay);
    System.out.println(name + "'s net pay is $" + formatNet + " \n");}

// Method for the welcome message, a void because it returns no values.
}
static void welcomeMessage ()
{
    System.out.println("Welcome to the CIS 220 Payroll Calculator!\n");
}

// Method that prompts the user to enter their name, scans it, then returns it.
static String getName ()
{
    String name;
    System.out.println("Please enter the employee's name(Enter a -1 when finished): ");
    name = console.nextLine();
    return name;

}

//Method that prompts the user to enter their pay rate, scans it, then returns it.    
static double getPay()
{
    double payRate;
    System.out.println("Please enter the employee's pay rate: ");
    payRate = console.nextDouble();
    console.nextLine();
    return payRate;
}

//Method that prompts the user to enter their hours worked, scans it, then returns it.        
static double getHours ()
{
    double hours;
    System.out.println("Please enter the employee's hours worked:");
    hours = console.nextDouble();
    console.nextLine();
    return hours;
}

//Method that uses the pay rate, hours worked that the user has entered.
//determines if the user qualifies for overtime pay or not, then calculates the overall    pay
//followed by tax reduction, then returns the netpay value.
static double calcNet (double pay, double hours)
{
   double net, grossPay;
   String formatNet;

    if(hours > 40)
    {
        grossPay = (pay * hours) * 1.5;
    }
    else
    {
        grossPay = pay * hours;
    }
    net = grossPay - (grossPay * .15);
    return net;
}


}

Answer 1

You could make your printMessage method (renamed from welcomeMessage) take a boolean parameter that tells the method if it should display the welcome or thank you message.

static void printMessage(final boolean isStarting) {
    if(isStarting) {
        // print the welcome message
        ...
    } else {
        // print the thank you message
        ...
    }
}

Then you call the method with true at the beginning of your program, and with false at the end.

Alternatively you could have a class variable:

private boolean hasPrintedWelcome = false;

And the printMessage method would be:

static void printMessage(final boolean isStarting) {
    if(!hasPrintedWelcome) {
        // print the welcome message
        ...
        hasPrintedWelcome = true;
    } else {
        // print the thank you message
        ...
    }
}

The first time the printMessage method is called, it will display the welcome message. Then the second time the method is called, and any subsequent times, the method will display the thank you message.

Answer 2

There is one problem with your program: you ask for the employee's name before entering in the while loop, so the name will be set only one time and never change, and so you will have an infinite loop.

What you have to do is to put another getName() call at the end of the loop, to allow the user to set a new name, and exit the loop:

// Every initialized variable receives the return statements from their respected methods.        
name  = getName();

while (!(name.equals("-1")))
{
    pay   = getPay (); 
    hours = getHours ();
    netPay = calcNet(pay,hours);

    // Formats the net pay to be 2 decimals.   
    formatNet = String.format("%.2f", netPay);
    System.out.println(name + "'s net pay is $" + formatNet + " \n");

    // Ask for the employee's name again
    name  = getName();
}

// Call the method to show the exit message here, like that: exitMessage();

And once you have fixed that, you can just call the method showing the exit message after the while loop.

EDIT: It seems that I misunderstood the question, and that the infinite loop was just a bug and not the actual question, see the other answer.