需要帮助格式化开关方法调用的输出

Question

This is for a class I'm taking where we were instructed to create a method that has two parameters (price and state) and then have the user enter in any price, and the method would run against it and output the cost from multiple states. I'm pretty proud of myself for figuring out how to make it mostly work. However, there's a couple of minor issues that I need help resolving.

• It only works if I type in an integer
• It goes more than two decimal spaces
• It shows the "case" value even though I don't ask it to.

Before I show my code, here's is an example output.

Enter price of donut:
5
Here's how much it would cost in each state
KY - 5.3
ky
OH - 5.2875
oh
IN - 5.35
in
TN - 5.35
tn
FL - 5.3
fl
WF - 5.3
wf

    import java.util.Scanner;
public class TaxCalculator {

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("Enter price of donut: ");
        double price = input.nextInt();
        String[] state=new String[6];
        state[0]="ky";
        state[1]="oh";
        state[2]="in";
        state[3]="tn";
        state[4]="fl";
        state[5]="wv";

        System.out.println("Here's how much your donut would cost in each state");
        System.out.println(addTax(price,state[0]));
        System.out.println(addTax(price,state[1]));
        System.out.println(addTax(price,state[2]));
        System.out.println(addTax(price,state[3]));
        System.out.println(addTax(price,state[4]));
        System.out.println(addTax(price,state[5]));
    }


public static String addTax( double price, String state ) {
    switch (state) {
    case "ky": System.out.println("KY - " + ((price*.06)+price));   
        break;
    case "oh": System.out.println("OH - " + ((price*.0575)+price));
        break;
    case "in": System.out.println("IN - " + ((price*.07)+price));
        break;
    case "tn": System.out.println("TN - " + ((price*.07)+price));   
        break;
    case "fl": System.out.println("FL - " + ((price*.06)+price));
        break;
    case "wv": System.out.println("WV - " + ((price*.06)+price));
        break;
    default: System.out.println("Invalid");
    break;
            }
    return state;
    }
}

Thanks Guys! I combined a lot of your suggestions and got exactly what I needed. I love this place.

import java.text.DecimalFormat;
import java.util.Scanner;
public class TaxCalculator {

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        System.out.println("Enter price of donut: ");
        double price = input.nextDouble();
        String[] state=new String[6];
        state[0]="ky";
        state[1]="oh";
        state[2]="in";
        state[3]="tn";
        state[4]="fl";
        state[5]="wv";

        System.out.println("Here's how much your donut would cost in each state");
        addTax(price,state[0]);
        addTax(price,state[1]);
        addTax(price,state[2]);
        addTax(price,state[3]);
        addTax(price,state[4]);
        addTax(price,state[5]);
    }


public static String addTax( double price, String state ) {
    String result=("");
    DecimalFormat money=new DecimalFormat("$#,###.00");
    switch (state) {
    case "ky": System.out.println("KY - " + money.format((price*.06)+price));   
        break;
    case "oh": System.out.println("OH - " + money.format((price*.0575)+price));
        break;
    case "in": System.out.println("IN - " + money.format((price*.07)+price));
        break;
    case "tn": System.out.println("TN - " + money.format((price*.07)+price));   
        break;
    case "fl": System.out.println("FL - " + money.format((price*.06)+price));
        break;
    case "wv": System.out.println("WV - " + money.format((price*.06)+price));
        break;
    default: System.out.println("Invalid");
    break;
            }

    return state;

    }
}

Answer 1

For point number 1, you are calling input.nextInt() for a double, you can simply call

input.nextDouble()

If you want two decimal places, you can use DecimalFormater like this

DecimalFormat df = new DecimalFormat();
df.setMaximumFractionDigits(2);
System.out.println(df.format(decimalNumber));

You can simplify the price calculation by doing price*1.06 etc

Your addTax method is returning a string, and you return state, this is why the case value is printed

Answer 2

Instead of:

System.out.println(addTax(price,state[0]));
    case "ky": System.out.println("KY - " + ((price*.06)+price));   
            break;
    return state; 

Do this:

System.out.printf("%.1d", addTax(price,state[0]));
     case "ky": String result = "KY - " + ((price*.06)+price);   
                break;
        return result;

Or something similar. That's also why you're printing state as you're returning it and using two System.out.println each call. Call Double.parseDouble instead of Integer.parseInt and you can input doubles.

Answer 3

1) amend your input to take nextDouble()

2) use String.format in your print statement like so:

System.out.println("KY - " + String.format("%.2f", ((price * 0.6) + price)));

3) remove System.out.println when calling the addTax method - as you're already doing the printing in this method

Answer 4

1) Try double price = input.nextDouble(); nextInt() will probably throw inputMissMatchException as you are fetching integer value from the input and assigning to the double.

2) You can use DecimalFormat df = new DecimalFormat("#.##"); and then System.out.println(df.format(value)) to round the double value to the 2 decimal spaces.

3) Remove all the print statements from the main method as the return value is State, it will print the state value for all the print statements in the main.

Answer 5

Good job, I would like to suggest a cleaner way to write it:

  public static void main(String[] args){
  System.out.println("Enter price of donut: ");
  Scanner input = new Scanner(System.in);
  double price = input.nextInt();

  Map<String, Double> multipliers = new LinkedHashMap<>();
  multipliers.put("KY", .06);
  multipliers.put("OH", .0575);
  multipliers.put("IN", .07);
  multipliers.put("TN", .07);
  multipliers.put("FL", .06);
  multipliers.put("WV", .06);

  System.out.println("Here's how much your donut would cost in each state");
  multipliers.forEach((x, y) -> System.out.println(x + " - " + (price + (price * y))));
  }