Question

我做了一个应用程序，我计算珠宝店的成本，并在主要方法中使用方法。

此方法必须使用三次，只更改一个参数。我也一直从Java中得到错误，说方法和变量已经定义，

这是我的代码：

import java.text.DecimalFormat;
import java.util.Scanner;
import javax.swing.JOptionPane;


public class JewelleryStore
{

    public static void main(String[] args)
    {

        double stateRate = 0.1;
        double luxuryRate = 0.2;
        double laborRate = 0.05;
        double extraCharge;
        int numOrdered;
        double diamondCost;
        double settingCost;
        double baseCost;
        double totalCost;
        double laborCost;
        double stateTax;
        double luxuryTax;
        double finalAmountDue;

        Scanner keyInput = new Scanner(System.in);

        System.out.println("What is the cost of the diamond?");
        diamondCost = keyInput.nextDouble();
        System.out.println("What is the cost of the setting?");
        settingCost = keyInput.nextDouble();
        System.out.println("How many rings are you ordering?");
        numOrdered = keyInput.nextInt();

        baseCost = diamondCost + settingCost;
        calcExtraCost(baseCost, laborRate);
        laborCost = extraCharge;
        calcExtraCost(baseCost, stateRate);
        stateTax = extraCharge;
        calcExtraCost(baseCost, luxuryRate);
        luxuryTax = extraCharge;
        totalCost = baseCost + laborCost + stateTax + luxuryTax;
        finalAmountDue = numOrdered*totalCost;
        DecimalFormat dollar = new DecimalFormat("0.00");
        JOptionPane.showMessageDialog(null, "Jasmine Jewelry INC:  TOTAL COST  BREAKDOWN" + "\nDiamond Cost: $" +dollar.format(diamondCost) + "\nSetting Cost: $" + dollar.format(settingCost) + "\nState Tax @ 10%: $" + dollar.format(stateTax) + "\nLuxury Tax  @ 20%: $" + dollar.format(luxuryTax)+"\nLabor Charge @ 5%: $"+dollar.format(laborCost)+"\nTotal Price: $" + dollar.format(diamondCost+settingCost+stateTax+luxuryTax+laborCost) +"\n\nNumberOrdered: " + numOrdered + "\n\nAmount Due $" + dollar.format(finalAmountDue));

    }
    public static double calcExtraCost(double diamond, double rate)
    {
        double extraCharge = diamond*rate;
        double diamond = baseCost;
        double rate = laborCost;

    }
    public static double calcExtraCost(double diamond2, double rate2)
    {
        double extracharge = diamond2*rate2;
        double diamond = baseCost;
        double rate2 = stateTax;
    }
    public static double calcExtraCost(double diamond2, double rate3)
    {
        double extracharge = diamond1*rate3;
        double diamond2 = baseCost;
        double rate3 = luxuryTax;
    }
}

Answer 1

哇，好的，所以你是Java新手。

编写一个计算额外成本一次的方法，并根据需要多次调用它，使用不同的参数，您将得到不同的结果。

类似的东西：

 public static double calcExtraCost(double value, double rate)
 {
    return value*rate;
 }

您可以根据以下某种比率为原始值添加一个百分比：

baseCost = baseCost + calcExtraCost(baseCost, laborRate);

我也推荐Head First Java！

Answer 2

你基本上是一次又一次地创建相同的方法，这是不需要的...只需创建一个方法，方法可以在运行时获得不同的值的伪代码：

public static double calcExtraCost(double diamond, double rate) { // do something return somedouble value computed }

在调用方法时，您需要将不同的速率作为输入calcExtraCost(diamond,rate1) or calcExtraCost(diamond,rate2) or calcExtraCost(diamond,rate3 )等传递，JVM足够聪明，可以调用相应的方法。另外你的逻辑没有意义请阅读http://docs.oracle.com/javase/tutorial/
的java基础知识

Answer 3

我认为这就是你所期待的

import java.text.DecimalFormat;
import java.util.Scanner;
import javax.swing.JOptionPane;


public class JewelleryStore
{

    public static void main(String[] args)
    {

        double stateRate = 0.1;
        double luxuryRate = 0.2;
        double laborRate = 0.05;
        double extraCharge;
        int numOrdered;
        double diamondCost;
        double settingCost;
        double baseCost;
        double totalCost;
        double laborCost;
        double stateTax;
        double luxuryTax;
        double finalAmountDue;

        Scanner keyInput = new Scanner(System.in);

        System.out.println("What is the cost of the diamond?");
        diamondCost = keyInput.nextDouble();
        System.out.println("What is the cost of the setting?");
        settingCost = keyInput.nextDouble();
        System.out.println("How many rings are you ordering?");
        numOrdered = keyInput.nextInt();

        baseCost = diamondCost + settingCost;
        extraCharge=calcExtraCost(baseCost, laborRate);
        laborCost = extraCharge;
        extraCharge=calcExtraCost(baseCost, stateRate);
        stateTax = extraCharge;
        extraCharge=calcExtraCost(baseCost, luxuryRate);
        luxuryTax = extraCharge;
        totalCost = baseCost + laborCost + stateTax + luxuryTax;
        finalAmountDue = numOrdered*totalCost;
        DecimalFormat dollar = new DecimalFormat("0.00");
        JOptionPane.showMessageDialog(null, "Jasmine Jewelry INC:  TOTAL COST  BREAKDOWN" + "\nDiamond Cost: $" +dollar.format(diamondCost) + "\nSetting Cost: $" + dollar.format(settingCost) + "\nState Tax @ 10%: $" + dollar.format(stateTax) + "\nLuxury Tax  @ 20%: $" + dollar.format(luxuryTax)+"\nLabor Charge @ 5%: $"+dollar.format(laborCost)+"\nTotal Price: $" + dollar.format(diamondCost+settingCost+stateTax+luxuryTax+laborCost) +"\n\nNumberOrdered: " + numOrdered + "\n\nAmount Due $" + dollar.format(finalAmountDue));

    }
    static double calcExtraCost(double diamond, double rate)
    {
        double extraCharge = diamond*rate;
        return extraCharge;

    }
}

如何在main方法中使用三次方法

3 个答案: