How do I limit the number of decimals printed for a double?

Question

This program works, except when the number of nJars is a multiple of 7, I will get an answer like $14.999999999999998. For 6, the output is 14.08. How do I fix exceptions for multiples of 7 so it will display something like $14.99?

import java.util.Scanner; public class Homework_17 {  private static int nJars, nCartons, totalOunces, OuncesTolbs, lbs;   public static void main(String[] args)   {    computeShippingCost();   }    public static void computeShippingCost()   {    System.out.print("Enter a number of jars: ");    Scanner kboard = new Scanner (System.in);    nJars = kboard.nextInt();    int nCartons = (nJars + 11) / 12;    int totalOunces = (nJars * 21) + (nCartons * 25);    int lbs = totalOunces / 16;    double shippingCost =  ((nCartons * 1.44) + (lbs + 1) * 0.96) + 3.0;     System.out.print("$" + shippingCost);    } } 

Answer 1

Use a DecimalFormatter:

double number = 0.9999999999999; DecimalFormat numberFormat = new DecimalFormat("#.00"); System.out.println(numberFormat.format(number)); 

Will give you "0.99". You can add or subtract 0 on the right side to get more or less decimals.

Or use '#' on the right to make the additional digits optional, as in with #.## (0.30) would drop the trailing 0 to become (0.3).

Answer 2

If you want to print/write double value at console then use System.out.printf() or System.out.format() methods.

System.out.printf("\n$%10.2f",shippingCost); System.out.printf("%n$%.2f",shippingCost);