Lucky Sevens [净变化计算]

每当我执行程序时，平均变化总是0，我不明白为什么。Lucky Sevens [净变化计算]

/*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 + "."); 
    } 
}

来源

2015-04-29 Casey Foster

您多久测试一次该程序？因为很可能你会放松一些游戏，然后再也不会回头看看maxDollars。因此，您绝不会将maxDollars更改为initialDollars。这给你0/100 - > 0 – ceekay

可能的重复[在Java中总是结果为零（0）？]（http://stackoverflow.com/questions/10455677/division-in-java-always-results-in -zero-0） – timrau

这个问题很可能是由于AverageWin是一个整数引起的。尝试将它改为浮点/双精度，以防止它被降低到下一个较低的整数（在您的情况下可能为0），并查看是否改变了结果。可能不是问题，但整数除法是第一件要吸引我的眼睛 – Sossenbinder

制作平均值温度作为双重变量。

平均赢的变化计算如下

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

来源

2015-04-29 09:05:52

我试过以下来得到正确的答案。

更改类型averageWin

double averageWin;

，然后计算公式

averageWin = (maxDollars - dollars)/100.0;

这将保存精度和给你正确的答案。

来源

2015-04-29 08:54:56 Yantraguru

Lucky Sevens [净变化计算]

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