C # arrays calculating the arithmetic mean, geometric mean, harmonic mean, median, and root mean square

1. function implementation

0) Print array

/// <summary>
/// 打印数组 /// </summary> /// <param name="arr">数组</param> /// <param name="numberPerLine">每行打印元素数量</param> /// <param name="digitAfterDot">小数点后保留位数</param> private static void PrintArray(double[] arr, int numberPerLine = 7, int digitAfterDot = 2) { //设定小数点后保留位数（函数ToString()的参数） string format = "#0."; while (true) { if (digitAfterDot <= 0) break; format += '0'; digitAfterDot--; } //打印数组 for (int i = 0; i < (arr.Length - 1) / numberPerLine + 1; i++) { for (int j = 0; j < numberPerLine; j++) { int index = i * numberPerLine + j; if (index < arr.Length) { Console.Write(arr[index].ToString(format) + "\t"); } } Console.WriteLine(); } }

1) Arithmetic Mean: (x1 + x2 + ... + xn) / n

/// <summary>
/// 计算算数平均数:（x1+x2+...+xn）/n /// </summary> /// <param name="arr">数组</param> /// <returns>算术平均数</returns> private static double ArithmeticMean(double[] arr) { double result = 0; foreach (double num in arr) { result += num; } return result / arr.Length; }

2) Geometric mean: (x1 * x2 * ... * xn) ^ (1 / n)

/// <summary>
/// 几何平均数：(x1*x2*...*xn)^(1/n) /// </summary> /// <param name="arr">数组</param> /// <returns>几何平均数</returns> private static double GeometricMean(double[] arr) { double result = 1; foreach (double num in arr) { result *= Math.Pow(num, 1.0 / arr.Length); } return result; }

3) Harmonic Mean: n / ((1 / x1) + (1 / x2) + ... + (1 / xn))

/// <summary>
/// 调和平均数：n/((1/x1)+(1/x2)+...+(1/xn)) /// </summary> /// <param name="arr">数组</param> /// <returns>调和平均数</returns> private static double HarmonicMean(double[] arr) { double temp = 0; foreach (double num in arr) { temp += (1.0 / num); } return arr.Length / temp; }

4) root mean square: ((x1 * x1 + x2 * x2 + ... + xn * xn) / n) ^ (1/2)

/// <summary>
/// 平方平均数：((x1*x1+x2*x2+...+xn*xn)/n)^(1/2) /// </summary> /// <param name="arr">数组</param> /// <returns>平方平均数</returns> private static double RootMeanSquare(double[] arr) { double temp = 0; foreach (double num in arr) { temp += (num * num); } return Math.Sqrt(temp / arr.Length); }

5) median

/// <summary>
/// 计算中位数 /// </summary> /// <param name="arr">数组</param> /// <returns></returns> private static double Median(double[] arr) { //为了不修改arr值，对数组的计算和修改在tempArr数组中进行 double[] tempArr = new double[arr.Length]; arr.CopyTo(tempArr, 0); //对数组进行排序 double temp; for (int i = 0; i < tempArr.Length; i++) { for (int j = i; j < tempArr.Length; j++) { if (tempArr[i] > tempArr[j]) { temp = tempArr[i]; tempArr[i] = tempArr[j]; tempArr[j] = temp; } } } //针对数组元素的奇偶分类讨论 if (tempArr.Length % 2 != 0) { return tempArr[arr.Length / 2 + 1]; } else { return (tempArr[tempArr.Length / 2] + tempArr[tempArr.Length / 2 + 1]) / 2.0; } }

2.Main function calls

static void Main(string[] args) { //一个数组 double[] arr = new double[] { 3, 2, 7, 4, 8, 8, 5, 5, 6, 5, 1, 8, 4, 9 }; //打印数组 PrintArray(arr); //调和平均数≤几何平均数≤算术平均数≤平方平均数 Console.WriteLine("算术平均数：" + ArithmeticMean(arr).ToString("#0.000")); Console.WriteLine("几何平均数：" + GeometricMean(arr).ToString("#0.000")); Console.WriteLine("调和平均数：" + HarmonicMean(arr).ToString("#0.000")); Console.WriteLine("平方平均数：" + RootMeanSquare(arr).ToString("#0.000")); Console.WriteLine("中位数：" + Median(arr).ToString("#0.000")); Console.ReadLine(); }

3. Run the sample