Question

我被分配了一个项目，我需要在其中创建一个程序，利用嵌套循环，用户可以输入一对骰子的边数和滚动次数。然后程序应该计算滚动某些数字组合的概率。该程序有点简单，因为它为您提供了所有代码，您只需要按正确的顺序放置它。我几天来一直在这个小工作，但我似乎无法使它工作。这就是我对代码所拥有的：

/**
* This program roll a dice with a selected amount of sides a selected amount of times.
*
* Timothy Pierce
* 1/5/2016
*
*/
import java.util.Scanner;
import java.util.Random;
class DiceProbability
{
  public static void main (String[] args)
  {
      //Initalizing variables
      int numRolls = 0;
      int numSides = 0;
      int match = 0;
      int sum = 0;

      //Accepting User Input
      Scanner in = new Scanner(System.in);
      System.out.print("Please enter the number of rolls: ");
      numRolls = in.nextInt();
      System.out.print("Please enter the number of sides on a dice: ");
      numSides = in.nextInt();
      System.out.print("\n Sum of Dice \t Probability \n");

      //Begin Loops
      for(int roll = 0; roll < numRolls; roll++)
      {
          for(sum = 2; sum <= (numSides*2); sum++)
          {
              int die1 = 0;
              int die2 = 0;
              Random randNum = new Random();
              die1 = randNum.nextInt(numSides)+1;
              die2 = randNum.nextInt(numSides)+1;
              if(die1 + die2 == sum)
              {
                  match = 0;
                  match++;
              }
              double probability = 0.0;
              probability = (double)match / numRolls * 100;
              System.out.println("     " + sum + "\t\t" + probability);
          }
      }
  }//End Method
}//End Class

所有代码都在那里，它只是没有正确的顺序。输出的格式应该是：行要求卷数，行要求边数，行标题有一列骰子和另一列豁免概率，然后循环应该“滚动骰子”并预测每个数字的概率。 IE它将有两列：一列是sum，另一列是概率。然后它应按顺序下降2,3,4,5,6等，并在其旁边的下一列中具有相应的概率。非常感谢所有帮助！

Answer 1

也许你的代码有问题，而不仅仅是订单。所以我试着写另一个，尝试一下。

/**
* This program roll a dice with a selected amount of sides a selected amount of times.
*
* Fergus Wang
* 1/6/2016
*
*/
import java.util.Scanner;
import java.util.Random;
class DiceProbability
{
  public static void main (String[] args)
  {
      //Initalizing variables
      int numRolls = 0;
      int numSides = 0;
      int match = 0;
      int sum = 0;

      //Accepting User Input
      Scanner in = new Scanner(System.in);
      System.out.print("Please enter the number of rolls: ");
      numRolls = in.nextInt();
      System.out.print("Please enter the number of sides on a dice: ");
      numSides = in.nextInt();
      System.out.print("\n Sum of Dice \t Probability \n");
      // A list to save match times.
      int[] matchList = new int[numSides*2+1];
      // creat a Random tool.
      Random randNum = new Random();
      // Begin Loops
      for(int roll = 0; roll < numRolls; roll++)
      {
          int die1 = 0;
          int die2 = 0;

          die1 = randNum.nextInt(numSides)+1;
          die2 = randNum.nextInt(numSides)+1;
          int tempSum = die1 + die2;
          // check sum value.
          for(sum = 2; sum <= (numSides*2); sum++)
          {
              if(tempSum == sum)
              {
                  matchList[sum-2]++;
              }
          }
      }

      for(int index = 0; index<numSides*2-1; index++){
          double probability = 0.0;
          probability = (double)matchList[index] / numRolls * 100;
          System.out.println("     " + (index+2) + "\t\t" + probability);
      }
  }//End Method
}//End Class

Answer 2

我认为代码中的问题是：＆＃34; die1＆＃34;和＆＃34; die2＆＃34;必须计算每个卷，而不是每个循环的＆＃34;总和＆＃34;值。＆＃34;匹配＆＃34;必须为＆＃34; sum＆＃34;的每个循环重置一个值。即使`die1 + die2 == sum＆＃39;也不行。根据解释，我只是重新排序你的代码（没有改变任何代码行）。这是我的实施：

import java.util.Scanner;
import java.util.Random;
class DiceProbability
{
public static void main (String[] args)
{
    //Initalizing variables
    int numRolls = 0;
    int numSides = 0;
    int match = 0;
    int sum = 0;

    //Accepting User Input
    Scanner in = new Scanner(System.in);
    System.out.print("Please enter the number of rolls: ");
    numRolls = in.nextInt();
    System.out.print("Please enter the number of sides on a dice: ");
    numSides = in.nextInt();
    System.out.print("\n Sum of Dice \t Probability \n");

    //Begin Loops
    for(int roll = 0; roll < numRolls; roll++)
    {
        int die1 = 0;
        int die2 = 0;
        Random randNum = new Random();

        die1 = randNum.nextInt(numSides)+1;
        die2 = randNum.nextInt(numSides)+1;

        for(sum = 2; sum <= (numSides*2); sum++)
        {
            match = 0;

            if(die1 + die2 == sum)
            {
                match++;
            }
            double probability = 0.0;

            probability = (double)match / numRolls * 100;
            System.out.println("     " + sum + "\t\t" + probability);
        }
    }
}//End Method
}//End Class

希望这有帮助！

嵌套循环和滚动骰子

2 个答案: