求随机数平均值方法 求随机数方差方法 求正态分布的随机数

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using System.Collections;
using System.Text.RegularExpressions;

namespace random
{
    class Program
    {

        //求随机数平均值方法
        static double Ave(double[] a)
        {
            double sum = 0;
            foreach (double d in a)
            {

                sum = sum + d;
            }
            double ave = sum / a.Length;

            return ave;
        }
        //求随机数方差方法
        static double Var(double[] v)
        {
            //    double tt = 2;
            //double mm = tt ^ 2;

            double sum1 = 0;
            for (int i = 0; i < v.Length; i++)
            {
                double temp = v[i] * v[i];
                sum1 = sum1 + temp;

            }

            double sum = 0;
            foreach (double d in v)
            {
                sum = sum + d;
            }

            double var = sum1 / v.Length - (sum / v.Length) * (sum / v.Length);
            return var;
        }

        //求正态分布的随机数
        static void Fenbu(double[] f)
        {
            //double fenbu=new double[f.Length ];
            for (int i = 0; i < f.Length; i++)
            {
                double a = 0, b = 0;
                a = Math.Sqrt((-2) * Math.Log(f[i], Math.E));
                b = Math.Cos(2 * Math.PI * f[i]);
                f[i] = a * b * 0.3 + 1;

            }

        }

        static void Main(string[] args)
        {

            //生成100个（0，1）之间的随机数
            Random ran = new Random();
            double[] dou = new double[100];
            for (int i = 0; i < dou.Length; i++)
            {
                dou[i] = ran.NextDouble();

            }

            //调用Ave方法、Var方法求得随机数均值和方差
            double avenum = Ave(dou);
            double varnum = Var(dou);

            //写入文件
            //将100个随机数，均值，方差保存到文件“d:\C#练习\SourceData.txt”中
            string Datapath = (@"d:\SourceData.txt");

            FileStream fs = new FileStream(Datapath, FileMode.Create);
            StreamWriter sw = new StreamWriter(fs);

            for (int j = 0; j < dou.Length; j++)
            {
                sw.WriteLine(dou[j]);

            }

            sw.Write("100个随机数均值和方差分别是{0}和{1}", avenum, varnum);
            sw.Close();


            //读取数据文件“d:\C#练习\SourceData.txt”
            FileStream fs1 = new FileStream(Datapath, FileMode.Open);
            StreamReader sr = new StreamReader(fs1);
            string temp = null;
            string str = null;
            while ((temp = sr.ReadLine()) != null)
            {
                str = str + temp + " ";
            }

            //对数组进行分割Regax
            Regex re = new Regex(" ");
            string[] str1 = re.Split(str);
            double[] nums = new double[str1.Length - 2];

            for (int i = 0; i < str1.Length - 2; i++)
            {

                nums[i] = Convert.ToDouble(str1[i]);
            }

            //调用正态分布随机函数,求均值和方差
            Fenbu(nums);
            double averesult = Ave(nums);
            double varresult = Var(nums);

            //写入文件
            //将100个随机数，均值，方差保存到文件“d:\C#练习\ResultData.txt”中
            string Resultpath = (@"d:\ResultData.txt");

            FileStream fs2 = new FileStream(Resultpath, FileMode.Create);
            StreamWriter sw1 = new StreamWriter(fs2);

            for (int j = 0; j < nums.Length; j++)
            {
                sw1.WriteLine(nums[j]);

            }

            sw1.Write("100个随机数均值和方差分别是{0}和{1}", averesult, varresult);
            sw1.Close();

            Console.ReadKey();

        }
    }
}