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();

}
}
}