C#实现求一组数据众数的方法

/// <summary>/// 结构：用于统计每个数出现的次数/// </summary>struct Stats{  //数字，出现的次数  public double Number;  public int Count;  //构造函数  public Stats(double n, int c)   {     Number = n;    Count = c;  }}/// <summary>/// 计算数组的众数/// </summary>/// <param name="array">数组</param>/// <param name="threshold">数量阈值，众数数量若多于次数则认为没有众数</param>/// <returns></returns>private static double[] ModeOf(double[] array, int threshold = 5){  //数组排序-统计各元素数量-按各元素数量排序-再统计最多的元素  //1.输入合法性检验  if (array == null || array.Length == 0 || threshold < 1)  {    return new double[] { };  }  //2.制作数组副本，后面的操作将不修改数组本身  double[] tempArray = new double[array.Length];  array.CopyTo(tempArray,0);  //3.数组排序  double temp;  for (int i = 0; i < tempArray.Length; i++)  {    for (int j = i; j < tempArray.Length; j++)    {      if (tempArray[i] < tempArray[j])      {        temp = tempArray[i];        tempArray[i] = tempArray[j];        tempArray[j] = temp;      }    }  }  //4.统计不同的元素数  int counter = 1;  for (int i = 1; i < tempArray.Length; i++)  {    if (tempArray[i] != tempArray[i - 1])    {      counter++;    }  }  //5.统计各个元素数量  int flag = 0;  Stats[] statsArray = new Stats[counter];  statsArray[flag].Number = tempArray[0];  statsArray[flag].Count = 1;  for (int i = 1; i < tempArray.Length; i++)  {    if (tempArray[i] == statsArray[flag].Number)    {      statsArray[flag].Count++;    }    else    {      flag++;      statsArray[flag].Number = tempArray[i];      statsArray[flag].Count = 1;    }  }  //6.按元素在原数组内数量（Count属性）降序排列  // 数量相等的元素则按大小升序排列  for (int i = 0; i < statsArray.Length; i++)  {    for (int j = i; j < statsArray.Length; j++)    {      if (statsArray[i].Count < statsArray[j].Count ||        (statsArray[i].Count == statsArray[j].Count &&          statsArray[i].Number > statsArray[j].Number))      {        temp = statsArray[i].Number;        statsArray[i].Number = statsArray[j].Number;        statsArray[j].Number = temp;        temp = statsArray[i].Count;        statsArray[i].Count = statsArray[j].Count;        statsArray[j].Count = (int)temp;      }    }  }  //7.统计众数数量  int count = 1;  if (statsArray.Length > threshold &&    statsArray[threshold].Count == statsArray[0].Count)  {    //众数多余阈值数量，则认为没有众数    return new double[] { };  }  else  {    for (int i = 1; i < statsArray.Length && i < threshold; i++)    {      if (statsArray[i].Count == statsArray[i - 1].Count)      {        count++;      }      else break;    }  }  //8.生成返回众数数组  double[] result = new double[count];  for (int i = 0; i < count; i++)  {    result[i] = statsArray[i].Number;  }  return result;}

static void Main(string[] args){  //示例数组1  double[] arr1 = new double[]   {    3, 2, 7, 4, 8, 8, 5,    5, 6, 5, 4, 3, 4, 9,    1, 1, 1, 2, 2, 0, 6  };  double[] d1 = ModeOf(arr1);  if (d1.Length != 0)  {    Console.Write("数组 1 有 " + d1.Length + " 个众数：");    for (int i = 0; i < d1.Length; i++)    {      Console.Write(d1[i] + " ");    }    Console.WriteLine();  }  else  {    Console.WriteLine("数组 1 没有众数");  }  //示例数组2  double[] arr2 = new double[]   {    1, 2, 3, 4, 5, 6  };  double[] d2 = ModeOf(arr2);  if (d2.Length != 0)  {    Console.Write("数组 2 有 " + d2.Length + " 个众数：");    for (int i = 0; i < d2.Length; i++)    {      Console.Write(d2[i] + " ");    }    Console.WriteLine();  }  else  {    Console.WriteLine("数组 2 没有众数");  }  Console.ReadLine();}