Error involving DecimalFormat

[kamikaze]

Hey guys, I'm a beginning java user and I'm working on a programming assignment that asks me to write a program that takes as input the marital status ("single" or "married", case insensitive) and the taxable income (double), and compute taxes.

My program was able to compile, but when I inputted a value for taxable income, I am receiving the following error message:

Enter your marital status (single or married):
single
Enter your taxable income:
10000
Exception in thread "main" java.lang.IllegalArgumentException: Cannot format given Object as a Number
at java.text.DecimalFormat.format(DecimalFormat.java: 487)
at java.text.Format.format(Format.java:140)
at Tax.main(Tax.java:73)

Here is my program:

// This program calculates the user's income tax

import java.util.Scanner;
import java.text.DecimalFormat;

public class Tax
{
public static void main(String [] args)
{
// Create a scanner object to read from the keyboard
Scanner keyboard = new Scanner(System.in);

// Create a DecimalFormat object
double tax;
DecimalFormat formatter = new DecimalFormat("0.00");

// Identifier declarations
double income;
String single, married;

// Marital Status: Single or Married
System.out.println("Enter your marital status (single or married): ");
String status = keyboard.nextLine();
if(status.equalsIgnoreCase("single"));

else if(status.equalsIgnoreCase("married"));

else
System.out.println("-- illegal marital status --");

// Taxable Income
System.out.println("Enter your taxable income: ");
income = keyboard.nextDouble();

// Marital Status: Single

if(status.equals("Single"));

else if(income > 0 && income <= 8000) {
tax = (income*.10);

} else if(income > 8000 && income <= 32000) {
tax =((income - 8000)*.15 + 800);

} else if(income > 32000) {
tax = ((income - 32000)*.25 + 4400);

} else {
System.out.println("-- illegal income --");
}
// Marital Status: Married

if(status.equals("Married"));

else if(income > 0 && income <= 16000) {
tax = (income*.10);

} else if(income > 16000 && income <= 64000) {
tax = ((income - 16000)*.15 + 1600);

} else if(income > 64000) {
tax = ((income - 64000)*.25 + 8800);

} else
System.out.println("-- illegal income --");

// Display Results
System.out.println("Your income tax is $" + formatter.format("tax"));
}
}

Any help or suggestions would be greatly appreciated!

[pbrockway2]

So which is line 73?

I'm guessing it's

System.out.println("Your income tax is $" + formatter.format("tax"));

The reason for the error is that format() expects a number (a numeric value) as an argument. It will format that numeric value: ie return a string representation. Now you are actually passing a three letter string as the argument. And format() has no way interpreting the three letters t-a-x as a number.

[pbrockway2]

Also could you tidy up the code?

Use the # button in the advanced reply pane so that your code appears within [CODE] and [/CODE] tags.

Also some of the lines look a bit odd (if blocks that do nothing):

String status = keyboard.nextLine();
 if(status.equalsIgnoreCase("single"));
 
 else if(status.equalsIgnoreCase("married"));
 
 else
 System.out.println("-- illegal marital status --");

is better written as

String status = keyboard.nextLine();
if(!status.equalsIgnoreCase("single") && !status.equalsIgnoreCase("married")) {
    System.out.println("-- illegal marital status --");
}

or

String status = keyboard.nextLine().toLowerCase();
if(!status.equals("single") && !status.equals("married")) {
    System.out.println("-- illegal marital status --");
}

[kamikaze]

Oh ok thanks! This is my first time using this forum so I was unfamiliar with the CODE tags. Anyways, I reformatted my program and was able to fix the issue as you mentioned earlier with line 73. I compiled and tested the program a few times, but some of the results did not come out correctly. For some reason, when I input "single", the answer is wrong, versus "married" where it is coming out correct. I checked the formulas, but they look fine.

Enter your marital status (single or married): 
single
Enter your taxable income: 
10000
Your income tax is $1000.0

The real answer is $1100.00

Enter your marital status (single or married): 
married
Enter your taxable income: 
64001  
Your income tax is $8800.25
// This program calculates the user's income tax

import java.util.Scanner;
import java.text.DecimalFormat;

public class Tax
{
   public static void main(String [] args)
   {
      // Create a scanner object to read from the keyboard
      Scanner keyboard = new Scanner(System.in);
      
      // Create a DecimalFormat object
      DecimalFormat formatter = new DecimalFormat("0.00");

      // Identifier declarations
      double tax = 0;
      double income;
      String single, married;
      
      // Marital Status: Single or Married 
      System.out.println("Enter your marital status (single or married): ");
      String status = keyboard.nextLine();
      if(!status.equalsIgnoreCase("single") && !status.equalsIgnoreCase("married")) {
         System.out.println("-- illegal marital status --");
       }
      // Taxable Income
      System.out.println("Enter your taxable income: ");
      income = keyboard.nextDouble();
      
      // Marital Status: Single

      if(status.equals("Single"));
         
      else if(income > 0 && income <= 8000) {
         tax = (income*.10);

      } else if(income > 8000 && income <= 32000) {
         tax = (800 + (income - 8000)*.15);
      
      } else if(income > 32000) {
         tax = (4400 + (income - 32000)*.25);
      
      } else {
         System.out.println("-- illegal income --");
      }
      // Marital Status: Married

      if(status.equals("Married"));
      
      else if(income > 0 && income <= 16000) {
         tax = (income*.10);
      
      } else if(income > 16000 && income <= 64000) {
         tax = (1600 + (income - 16000)*.15);
      
      } else if(income > 64000) {
         tax = (8800 + (income-64000)*.25);
      
      } else
         System.out.println("-- illegal income --");

      // Display Results
      System.out.println("Your income tax is $" + tax);
   }
}

[pbrockway2]

You still have a couple of if blocks that appear o do nothing.

I suspect that when you write:

// Marital Status: Single

if(status.equals("Single"));    // <--- ???
         
else if(income > 0 && income <= 8000) {
     tax = (income*.10);

} else if(income > 8000 && income <= 32000) {
     tax = (800 + (income - 8000)*.15);
      
} else if(income > 32000) {
     tax = (4400 + (income - 32000)*.25);
      
} else {
     System.out.println("-- illegal income --");
}
// Marital Status: Married

if(status.equals("Married"));    // <---- ???
      
else if(income > 0 && income <= 16000) {
     tax = (income*.10);
      
} // etc etc etc

that you really mean something like

// Marital Status: Single

if(status.equals("Single")) {
         
    if(income > 0 && income <= 8000) {
       tax = (income*.10);

    } else if(income > 8000 && income <= 32000) {
       tax = (800 + (income - 8000)*.15);
      
    } else if(income > 32000) {
       tax = (4400 + (income - 32000)*.25);
      
    } else {
       System.out.println("-- illegal income --");
    }

} else if(status.equals("Married")) {
    // Marital Status: Married
     
    if(income > 0 && income <= 16000) {
       tax = (income*.10);
      
    } // etc etc etc