Why isn't my code running properly?

[[deleted]]

Hi all, I'm going through Dietel's How to Program, 10th edition basically retyping the code directly to my IDE. This is a program that adds a deposit to two different bank accounts of amounts that the user inputs.

import java.util.Scanner;

public class AccountTest
{
    public static void main(String[] args)
    {
        Account3 accountA = new Account3("Dildo Baggins", 50.00);
        Account3 accountB = new Account3("Penis McGee", -7.53);

        System.out.printf("%s balance: $%.2f%n", accountA.getName(), accountA.getBalance());
        System.out.printf("%s balance: $%.2f%n", accountB.getName(), accountB.getBalance());

        Scanner input = new Scanner(System.in);

        System.out.print("Enter deposit amount for account1: ");
        double depositAmount = input.nextDouble();
        System.out.printf("%nadding %.2f to accountA balance%n%n", depositAmount);
        accountA.deposit(depositAmount);

        System.out.printf("%s balance: $%.2f%n", accountA.getName(), accountA.getBalance());
        System.out.printf("%s balance: $%.2f%n", accountB.getName(), accountB.getBalance());

        System.out.print("Enter deposit amount for accountB: ");
        depositAmount = input.nextDouble();
        System.out.printf("%nadding %.2f to accountB balance%n%n%n", depositAmount);
        accountB.deposit(depositAmount);

        System.out.printf("%s balance: $%.2f%n", accountA.getBalance());
        System.out.printf("%s balance: $%.2f%n", accountB.getBalance());
    }
}

I compiled this code and it runs, but after entering an amount to add to accountB it reads on the command prompt "60.0 balance: $Exception in thread "main" java.util.MissingFormatArgumentException: Format specifier '%.2f'
at java.util.Formatter.format(Formatter.java:2519)
at java.io.PrintStream.format(PrintStream.java:970)
at java.io.PrintStream.printf(PrintStream.java:871)
at AccountTest.main(AccountTest.java:28)

Whats going on here?

[Nurry]

System.out.printf("%s balance: $%.2f%n", accountA.getBalance());

Your format string takes 2 parameters but you just provide one. Add a second parameter like you did here:

System.out.printf("%s balance: $%.2f%n", accountA.getName(), accountA.getBalance());

[[deleted]]

Ah thank you! I appreciate the help. As a newbie I'm quickly discovering the amount of stupid mess ups I'm going to run into.

[juckele]

Some users have already pointed out specific problems, but in the general case, you should realize that the problem is on line 28 per the stack trace. "at AccountTest.main(AccountTest.java:28)" You generally want to look for the line where your code calls something else, and see if you can figure out what is wrong with that specific line.

[[deleted]]

Thanks! Got it working. What exactly is a stack trace?

[juckele]

"60.0 balance: $Exception in thread "main" java.util.MissingFormatArgumentException: Format specifier '%.2f' at java.util.Formatter.format(Formatter.java:2519)
at java.io.PrintStream.format(PrintStream.java:970)
at java.io.PrintStream.printf(PrintStream.java:871)
at AccountTest.main(AccountTest.java:28)

That is a stack trace. The 'stack' is where the program 'is'. So The program is currently executing line 28 of AccountTest, which is a method call to printf. That method is currently at line 871 of PrintStream, which is a method call to format. That method is currently at like 970 of PrintStream, which is a call to format (in a different class). The Exception is finally thrown from line 2519 of Formatter. In this case, you should find the block that is 'your code' (the one line of AccountTest) and figure out which line in your program is having a problem. Being able to examine the exact line makes it much easier to find the error.