Java开发网 - 关于多线程的一道问题！

Topic: 关于多线程的一道问题！

1.关于多线程的一道问题！	Copy to clipboard
Posted by: zerog Posted on: 2006-08-23 10:51 “编程生产100个1到6之间的随机数，统计1到6每个数出现的概率。并且在三个线程中各生成100个1到6之间的随机数，最后统计每个数字出现的总概率。” 这个问题比较难，希望why不惜赐教一下，大虾们也帮解答一下这道题？

2.Re:关于多线程的一道问题！ [Re: zerog]	Copy to clipboard
Posted by: why Posted on: 2006-08-23 19:41 Please write code first. Write the method that 生产1到6之间的随机数 then write the method that 统计每个数字出现 if you have problem with 线程, let us know then but write code first!

3.Re:关于多线程的一道问题！ [Re: zerog]

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Posted by: Stub
Posted on: 2006-08-23 20:02

下面，是在下的试着写出的程序。在下也是个JAVA初学者，虽然有很多问题解绝不了，但这个问题还是很简单的。LZ请在自己试着写过程序之后，在来看看在下的代码。Don't be afraid to try.

欢迎对在下的代码提提意见^_^


public class TestRandomMath extends Thread
{
  public static void main (String [] argv)
  {
    TestRandomMath t1 = new TestRandomMath();
    TestRandomMath t2 = new TestRandomMath();
    TestRandomMath t3 = new TestRandomMath();
    t1.setPriority(Thread.MAX_PRIORITY);
    t1.start();
    t2.setPriority(Thread.MAX_PRIORITY);
    t2.start();
    t3.setPriority(Thread.MAX_PRIORITY);
    t3.start();
  }
  
  private int random, one, two, three, four, five, six;
  
  public void run()
  {
    for (int i = 0; i < 100; i++)
    {
      random = (int) (Math.random()*6+1);
      switch (random)
      {
        case 1:
          one = ++ one;
          System.out.print(1);
          break;
        case 2:
          two = ++ two;
          System.out.print(2);
          break;
        case 3:
          three = ++ three;
          System.out.print(3);
          break;
        case 4:
          four = ++ four;
          System.out.print(4);
          break;
        case 5:
          five = ++ five;
          System.out.print(5);
          break;
        case 6:
          six = ++ six;
          System.out.print(6);
          break;
      }
    }

    System.out.println();
    int sum = one+two+three+four+five+six;
    System.out.println("总共得到了"+sum+"个");
    System.out.println("出现１的概率为"+one+"%");
    System.out.println("出现２的概率为"+two+"%");
    System.out.println("出现３的概率为"+three+"%");
    System.out.println("出现４的概率为"+four+"%");
    System.out.println("出现５的概率为"+five+"%");
    System.out.println("出现６的概率为"+six+"%");

  }

}

4.Re:关于多线程的一道问题！ [Re: Stub]	Copy to clipboard
Posted by: colo007 Posted on: 2006-08-23 20:44 Stub wrote: random = (int) (Math.random()6+1); 我提出自己的小疑问，是否这里的应该换成 % ？呵呵？

5.Re:关于多线程的一道问题！ [Re: colo007]	Copy to clipboard
Posted by: why Posted on: 2006-08-24 02:08 colo007 wrote: 我提出自己的小疑问，是否这里的*应该换成 % ？ Why do you think so? 0.0 <= Math.random() < 1.0

6.Re:关于多线程的一道问题！ [Re: zerog]	Copy to clipboard
Posted by: d_ai_w_ei Posted on: 2006-08-26 16:33 如果将"one = ++ one"写成"++one"是否更清晰些呢?

7.Re:关于多线程的一道问题！ [Re: zerog]

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Posted by: zerog
Posted on: 2006-08-30 23:29

非常感谢大虾们的解答，最近特忙忘记跟大家说声谢谢了，我把这道题我写的代码放上来，欢迎大家对我写的提意见，还有我是个初学者，不知道怎么背景是黑色的写代码，我都是用eclipse来写的，有谁能告诉我是怎么弄的吗？


public class text {
  public static void main(String[] args) throws InterruptedException {
    Data data = new Data();
    Stat stat = new Stat();
    stat.setMap(data.getMap());
    stat.start();
    stat.join();
    data.print();
  }
}

class Stat extends Thread {
  public Stat() {}
  public Stat(String s) {super(s);}
  public Stat(ThreadGroup group, String s) {super(group, s);}
  private Map<Integer, Double> map;
  public void setMap(Map<Integer, Double> map) {
    this.map = map;
  }

  public void run() {
    for(int i = 0; i < 100; i++) {
      Integer number = new Integer(Math.random(1, 6));
      if(map.containsKey(number))
        map.put(number, new Double(map.get(number).intValue() + 1));
      else
        map.put(number, new Double(1));
    }
  }
}

class Data {
  private Map<Integer, Double> map = Collections.synchronizedMap(new HashMap<Integer, Double>());
  public Map<Integer, Double> getMap() {
    return map;
  }
  
  public void print() {
    for(int i = 1; i < 7; i++){
      map.put(new Integer(i), new Double(map.get(new Integer(i)).doubleValue() / 300));
    }
    System.out.println(map);
  }
}