namespace zqf620.Demo.WeightingNumber
{
 /// <summary>
 /// WeightingNumber 的摘要说明。
 /// </summary>
 public class WeightingNumber
 {
  public WeightingNumber()
  {
   //
   // TODO: 在此处添加构造函数逻辑
   //
  }

  public WeightingNumber(params uint[] weightings) //构造函数
  {
   this.setWeighting(weightings);
  }

  private ArrayList _weightings = new ArrayList();
  private int _count = 0;

  public bool setWeighting(params uint[] weightings) //设置一组权重，要求所有权重之和为100
  {
   uint count = 0;
   uint min,max;
   foreach(uint i in weightings)
   {
    min = count*100;
    max = min + i*100 -1;
    zone tmp = new zone(min,max);
    _weightings.Add(tmp);
    count += i;
   }

   if (count != 100)
    return false;
   else
   {
    _count = _weightings.Count;
    return true;
   }
  }
  
  public int GetIndex()  //返回一组数的一个下标
  {
   int index = -1;

   if(_count == 0)
    return index;

   Random rdm = new Random(unchecked((int)DateTime.Now.Ticks));
   int num = rdm.Next(0,9999);
//   Debug.Write(num);   

            for(int i = 0; i < this._count; i++)
   {
    zone tmp = (zone)_weightings[i];
    if(num >= tmp.minValue && num <= tmp.maxValue)
    {
     index = i;
     return index;
    }
   }
   return index;
  }

  struct zone  //用于保存一个minValue到maxValue区域
  {
   public uint minValue,maxValue;
   
   public zone(uint min,uint max)
   {
    minValue = min;
    maxValue = max;
   }
  }

  
  static void Main()
  {
   int[] chars = new int[]{0,1,2,3,4};   //一组数，0 1 2 3 4
   //0出现的概率为10%，1出现的概率为20%，2出现的概率为40％，…… 这些概率值加起来必须为100
   WeightingNumber wn = new WeightingNumber(10,20,40,15,15); 

   ArrayList result = new ArrayList(200);

   for(int i = 0; i < 200 ;i++) //抽取200次
   {
    Thread.Sleep(1);
    int index = wn.GetIndex(); //抽取下标
    result.Add(chars[index]);  //得到下标对应的数字
//    Console.WriteLine(chars[index]);
   }
   
   //以下是打印抽取结果的代码
   result.Sort();

   for(int i = 0 ; i < result.Count ; i++)
   {
    if(i !=0)
    {
     if((int)result[i-1] != (int)result[i])
      Console.WriteLine();
    }
    Console.Write("{0}",result[i]);
   }

   Console.ReadLine();
  }
 }
}