CODEWITHSUNDEEP
java
just_chillin
just_chillin

Reputation: 31

java.util.IllegalFormatPrecisionException error when rounding to the two-decimal places using printf

I'm a new java coder and am getting an error when using printf to round a value to twodecimal places. Can anyone help me understand why, and how to resolve the error?

Code

import java.util.Scanner;

public class Demo
{

    public static void main(String[] args)
    {

        int age = 0;
        int count = 0;
        int round = 0;


        while ((age < 12) || (age > 18))
        {

            Scanner input = new Scanner(System.in);
            System.out.print("Enter a non-teen age: ");
            age = input.nextInt();          

            if ((age < 12) || (age > 18))
            {
                count = count + 1;
                round = round + age;
            }
        }

        System.out.println("Opps! " + age + " is a teen's age.");
        System.out.println("Number of non-teens entered: " + count);
        System.out.printf("Average of non-teens ages entered: %.2d",       round);
    }


}

Error:

Exception in thread "main" java.util.IllegalFormatPrecisionException: 2
at java.util.Formatter$FormatSpecifier.checkInteger(Unknown Source)
at java.util.Formatter$FormatSpecifier.<init>(Unknown Source)
at java.util.Formatter.parse(Unknown Source)
at java.util.Formatter.format(Unknown Source)
at java.io.PrintStream.format(Unknown Source)
at java.io.PrintStream.printf(Unknown Source)
 Demo.main(Demo.java:31)

Upvotes: 3

Views: 8050

Answers (3)

vijayraj34
vijayraj34

Reputation: 2415

Because your format specifiers don't match input arguments used in the printf method.

Use %f rather than %d as the format specifier character for int/double values.

Upvotes: 0

TmTron
TmTron

Reputation: 19381

I guess the error is in this line

System.out.printf("Average of non-teens ages entered: %.2d",       round);

'.2' does not make sense for decimal integers. Remove it:

System.out.printf("Average of non-teens ages entered: %d",       round);

Upvotes: 3

Dzmitry Kushnarou
Dzmitry Kushnarou

Reputation: 566

Integers can’t have decimal places since they don’t have a fractional part. Try using a float instead:

"Average of non-teens ages entered: %.2f"

Also, your round variable is currently storing a sum, so you need to divide it by count to get the average age:

System.out.printf("Average of non-teens ages entered: %.2f",  (float)round / count);

Upvotes: 0

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