用Java循环...？

Question

I'm having trouble looping this program. I believe everything in the private method is correct, however, I cannot get the main method right to create the loop. The code is below and a description of what it does is in the comments.

Thanks.

import java.util.Random;

/**
 * This program rolls the dice three times and the profit is the sum of the face
 * values that are obtained. Fives do not count and no roll after a five counts.
 * The program will be run 1 million times and the results will be averaged
 *
 * @author --
 */
public class FatalFives {

    public static void main(String[] args) {
        final int TRIALS = 1000000;
        int count = 0;

        while (count < TRIALS) {
            count++;
        }

        double avg = (double) profit / TRIALS;
        System.out.println("Your average winnings are: $" + avg);
    }

    private static int FatalFive() {
        Random rand = new Random();

        int profit = 0;

        int die1 = 1 + rand.nextInt(6);
        int die2 = 1 + rand.nextInt(6);
        int die3 = 1 + rand.nextInt(6);

        if (die1 == 5) {
            //System.out.println("You're unlucky, no profit");
            profit = 0;
        } else if (die1 != 5 && die2 == 5) {
            //System.out.println("Congrats! You won $" + die1);
            profit = (die1);
        } else if (die3 == 5) {
            //System.out.println("Congrats! You won $" + die1 + die2);
            profit = (die1 + die2);
        } else if (die1 != 5 && die2 != 5 && die3 != 5) {
            //System.out.println("Congrats! You won $" + (die1 + die2 + die3));
            profit = (die1 + die2 + die3);
        }
        return profit;
    }
}

Answer 1

• Random should be initialized one time. It may create the same results each time
• you private method is never called in the loop. Why?
• the profit is not defined in the mail method to store the profit returned by the private method

You should change:

    while (count < TRIALS) {
        count++;
    }

to something like:

    long profit = 0;
    while (count < TRIALS) {
        profit += FatalFive();
        count++;
    }

Please note: A method, except the constructor, should NOT be named like the class. rename your method to something like "rollFatalFive()".