Question

由于某些原因，未计算方法grossPay()和fedTax()。

如何返回grossPay()结果grosspay？
如何返回fedTax()结果taxtotal？
我在哪里计算totalpay = grosspay - taxtotal？

由于我无法返回taxtotal我无法判断它是否有效，但是我是否正确调用grosspay和dependents来计算taxtotal？< / LI>

谢谢！

import java.util.Scanner;

public class WorkPay {

public static void main(String args[]) {
    WorkPay wagecalc = new WorkPay();   // 1. Instantiate the object WorkPay
    WorkPay input = new WorkPay();      // 2. Reference the method to prompt for inputs
    input.prompt4data();
    input.display();                    // 3. Reference the method to display the results
}

public void prompt4data() {
    Scanner console = new Scanner(System.in);
    System.out.println("How many hours have you worked?");
    hours = console.nextDouble();
    System.out.println("What is your wage rate?");
    wage_rate = console.nextDouble();
    System.out.println("How many dependents do you have?");
    dependents = console.nextInt();
}

// private instance variables
    private double hours;
    private double wage_rate;
    private int dependents;
    private double grosspay;
    private double totalpay;
    private double tax;
    private double dependenttax;
    private double taxtotal;

public double grossPay() {
    double total1 = 0;
    double total2 = 0;
    double total3 = 0;
    if (hours <= 40) {
        total1 = wage_rate * hours;
        grosspay = total1;
    }
    else if (hours > 40 && hours <= 60) {
        total2 = total1 + (wage_rate * 1.5) * (hours - 40);
        grosspay = total2;
    }
    else {
        total3 = total2 + (wage_rate * 2) * (hours - 60); 
        grosspay = total3;
    }
    return grosspay;
}

public void fedTax() {
    tax = (0.10 * grosspay);
    dependenttax = (25 * dependents);
    taxtotal = tax + dependenttax;
    if (tax < 0)
        System.out.println("Taxt withheld can't be less than 0.");
}

public void display() {
    System.out.println("The hours worked is: " + hours);
    System.out.println("The hoursly rate is: " + wage_rate);
    System.out.println("The number of dependents is: " + dependents);
    System.out.println("The gross income is: " + grosspay);
    System.out.println("The federal tax withheld is: " + taxtotal);
    System.out.println("The take home pay is: " + totalpay);
}
}

Answer 1

调用它们，或者使用getter（更好），getters，aka accessors，是一种命名约定，其中方法以get为前缀（另请参阅Java - Using Accessor and Mutator methods）：

public double getGrossPay() {
    double grosspay = 0; //local now (remove field)
    double total1 = 0;
    double total2 = 0;
    double total3 = 0;
    if (hours <= 40) {
        total1 = wage_rate * hours;
        grosspay = total1;
    }
    else if (hours > 40 && hours <= 60) {
        total2 = total1 + (wage_rate * 1.5) * (hours - 40);
        grosspay = total2;
    }
    else {
        total3 = total2 + (wage_rate * 2) * (hours - 60); 
        grosspay = total3;
    }
    return grosspay;
}

public void display() {
    ...
    System.out.println("The gross income is: " + getGrossPay());
    ...
}

这样总薪酬总是正确的，没有任何字段可以过时。

getGrossPay您还有其他一些问题：各种小计并非都计算完毕，但我会让您解决这个问题，或者您可以看看这对您是否有意义：

public double getGrossPay() {
    double grosspay = wage_rate * hours;
    if (hours > 40) grosspay += wage_rate * (hours - 40) * 0.5;
    if (hours > 60) grosspay += wage_rate * (hours - 60) * 0.5;
    return grosspay;
}

Answer 2

由于您使用实例变量进行所有计算，因此无需从方法返回。您可以继续更新变量并在最后打印它们。

在这里，我对您的计划进行了一些更改。

import java.util.Scanner;

    public class WorkPay {

        // private instance variables
        private double hours;
        private double wage_rate;
        private int dependents;
        private double grosspay;
        private double totalpay;
        private double tax;
        private double dependenttax;
        private double taxtotal;

        public static void main(String args[]) {
            WorkPay input = new WorkPay(); // 2. Reference the method to prompt for
                                           // inputs
            input.prompt4data();
            input.grossPay();
            input.fedTax();
            input.display(); // 3. Reference the method to display the results
        }

        public void prompt4data() {
            Scanner console = new Scanner(System.in);
            System.out.println("How many hours have you worked?");
            hours = console.nextDouble();
            System.out.println("What is your wage rate?");
            wage_rate = console.nextDouble();
            System.out.println("How many dependents do you have?");
            dependents = console.nextInt();
        }

        public void grossPay() {
            double total1 = 0;
            double total2 = 0;
            double total3 = 0;
            if (hours <= 40) {
                total1 = wage_rate * hours;
                grosspay = total1;
            } else if (hours > 40 && hours <= 60) {
                total2 = total1 + (wage_rate * 1.5) * (hours - 40);
                grosspay = total2;
            } else {
                total3 = total2 + (wage_rate * 2) * (hours - 60);
                grosspay = total3;
            }
        }

        public void fedTax() {
            tax = (0.10 * grosspay);
            dependenttax = (25 * dependents);
            taxtotal = tax + dependenttax;
            if (tax < 0)
                System.out.println("Taxt withheld can't be less than 0.");
        }

        public void display() {
            System.out.println("The hours worked is: " + hours);
            System.out.println("The hoursly rate is: " + wage_rate);
            System.out.println("The number of dependents is: " + dependents);
            System.out.println("The gross income is: " + grosspay);
            System.out.println("The federal tax withheld is: " + taxtotal);
            System.out.println("The take home pay is: " + totalpay);
        }
    }

Answer 3

让我们从你的领域开始吧。你只需要少数几个。

// private instance variables
private double hours;
private double wage_rate;
private int dependents;

这三个字段（以及wage_rate应该wageRate符合惯例）是您需要的唯一字段。应计算所有其他值。

接下来，由于您计算的值彼此依赖（doubleTime包括您的基本费率和时间的一半），您应该预先计算这些值。这不应该有任何风险，因为例如，如果你只有51个小时的工作时，你不在乎doubleTime是否不准确。

public double grossPay() {
    double baseRate = wage_rate * hours;
    double timeAndAHalf = baseRate + (wage_rate * 1.5) * (hours - 40);
    double doubleTime = timeAndAHalf + (wage_rate * 2) * (hours - 60);
    if (hours <= 40) {
        return baseRate;
    } else if (hours > 40 && hours <= 60) {
        return timeAndAHalf;
    } else {
       return doubleTime;
    }
    return grosspay;
}

第三，让我们仔细研究fedTax方法。好消息是你不能在其他任何地方使用dependenttax（真的应该是dependentTax）或tax，所以你需要做的只是明确的返回您计算的值。不要忘记实际调用 grossPay方法，因为您需要将其作为计算的一部分。

public double fedTax() {
    tax = (0.10 * grossPay());
    dependenttax = (25 * dependents);
    return tax + dependenttax;
}

最后，剩下的就是将您必须计算的值打印到输入字段的最后部分...

// Method call to...something that does things with gross pay
System.out.println("The gross income is: " + _____);
// Method call to...something that does things with tax...
System.out.println("The federal tax withheld is: " + _____);
// What's the net pay again?
System.out.println("The take home pay is: " + ____);

...但我将作为读者的明确练习。

如何使变量适用于多种方法？

3 个答案: