Question

每当我执行程序时，平均更改总是为0，我不明白为什么。

/*LuckySevens.java

Simulate the game of lucky sevens until all funds are depleted.
1) Rules:
        roll two dice
        if the sum equals 7, win $4, else lose $1
2) The inputs are:
        the amount of money the user is prepared to lose
3) Computations:
        use the random number generator to simulate rolling the dice
        loop until the funds are depleted
        count the number of rolls
        keep track of the maximum amount
4) The outputs are:
        the number of rolls it takes to deplete the funds
        the maximum amount
        the average net change after 100 rolls
*/

import java.util.Scanner;
import java.util.Random;

public class LuckySevens {
   public static void main (String [] args) {

      Scanner reader = new Scanner(System.in);
      Random generator = new Random();

      int die1, die2,       // two dice
          dollars,          // initial number of dollars (input)
          countAtMax,       // count when the maximum is achieved
          count,            // number of rolls to reach depletion
          maxDollars,       // maximum amount held by the gambler
          averageWin,       // the average net change after 100 rolls
          initialDollars;   // initial amount of money user has 




      // Request the input
      System.out.print("How many dollars do you have? ");
      dollars = reader.nextInt();

      // Initialize variables
      maxDollars = dollars;
      initialDollars = dollars;
      countAtMax = 0;
      count = 0;

      // Loop until the money is gone
      while (dollars > 0){
         count++;

         // Roll the dice.
         die1 = generator.nextInt (6) + 1; // 1-6
         die2 = generator.nextInt (6) + 1; // 1-6

         // Calculate the winnings or losses
         if (die1 + die2 == 7)
            dollars += 4;
         else
            dollars -= 1;


         // If this is a new maximum, remember it
         if (dollars > maxDollars){
            maxDollars = dollars;
            countAtMax = count;
         }

         /* TODO:FIX BELOW STATEMENT
                 it always returns influx as 0 */

         if (count == 100) {
           averageWin = ((maxDollars - initialDollars) / 100);
            System.out.println ("In the first 100 rolls there an average money influx of " + averageWin + " per roll.") ;

         }
      }

      // Display the results
      System.out.println
         ("You went broke after " + count + " rolls.\n" +
          "You should have quit after " + countAtMax +
          " rolls when you had $" + maxDollars + ".");
   }
}

Answer 1

将 averageWin 设为 double 变量。

将平均胜利的计算更改为

averageWin =（（double）maxDollars - （double）initialDollars）/ 100;

Lucky Sevens [净变动计算]

1 个答案: