Java Dice Simulation

Question

I am writing a dice roll program. The code works fine in working out the face and number of frequencies. How I can calculate the percentage for the frequency of each face?

 import java.util.Random;

 public class Dice{
    public static void main (String[] args){
      Random random = new Random(); // Generates random numbers
      int[] array = new int[ 7 ]; // Declares the array

      //Roll the die 10000 times
      for ( int roll = 1; roll <=10000; roll++ ) {
        /*++array[1 + random.nextInt(6)];*/
        int dice = 1 + random.nextInt(6);
        ++array[dice];
      }
      System.out.printf("%s%10s\n", "Face", "Frequency");

     // outputs array values
      for (int face = 1; face < array.length; face++) {
         System.out.printf("%4d%10d\n", face, array[face]);
      }
   }
}

Answer 1

The frequency is just the count of each face divided by the total count.

for (int face = 1; face < array.length; face++) {
    System.out.printf("%4d%10f\n", face, array[face] / 10000.0);
}

The division must be performed with a double value (otherwise, an integer division would be performed and the result would always be 0), explaining why I divided with 10000.0 and not 10000.

I also changed the String format from %10d to %10f because you want to print a decimal number, not an integer. See the Formatter Javadoc for the list of all token.

Also, I suggest you make a local variable holding the total count so as not to repeat it twice.