What am I doing wrong? Java IllegalFormatConversionException

Question

I have some code for calculating properties of a circle:

package circleinfo;

import java.util.Scanner;

public class Circleinfo {

    public static void ma         


        

Answer 1

(r*2) will be an int and not a float as r is int and 2 is int. Use %d instead

%c          char    Character
%d          int         Signed decimal integer.  
%e, %E      float       Real number, scientific notation (lowercase or uppercase exponent marker)
%f         float    Real number, standard notation.

Answer 2

r is an int, so r*2 is also an int, meaning that in your second print statement %f cannot be used. Try %d there instead.

Recall that %f is for floating point numbers while %d is for integers. This is outlined in the documentation of Formatter (see Format String Syntax).

Answer 3

This is because you had to put %d format instead of %f in the result of the diameter

import java.util.Scanner;
public class CircleInfo{
    public static void main(String[] args){

            Scanner input = new Scanner(System.in);
            int radio;
            System.out.print("Input radio: ");
            radio = input.nextInt();

            System.out.printf("%s%d%n","Diameter= ",(2*radio));
            System.out.printf("%s%f%n","Area= ",(Math.PI*radio*radio));
            System.out.printf("%s%f%n","Circumference = ",(2*Math.PI*radio));
    }
}