You might think that the distribution of bytes in the guides was random or at least very flat. What is the reason Guid.NewGuid always makes guids that contains 4? whose string representation contains 4?
it
Guid.NewGuid (). ToString ("N"). Contains ("4")
always true.
A quick test shows that most bytes are found in about 85% of guides, but 4 occurs in 100%. Maybe it doesn’t matter, but I would like to know why.
[Edit]
I was not terribly clear, so I was edited to improve the clarity of my question.
Run it. Not quite deep, but funny.
using System;
using System.Diagnostics;
namespace ConsoleApplication1
{
class Program
{
static bool paused, exit;
static void Main(string[] args)
{
Console.WindowHeight = (int)(0.8*Console.LargestWindowHeight);
var reportInterval = TimeSpan.FromSeconds(0.15);
WriteLine(ConsoleColor.White, "X key to exit.");
Guid guid;
byte[] bytes;
long guidCount = 0;
var counts = new long[256];
var watch = Stopwatch.StartNew();
var cursorPos = new CursorLocation();
while (!exit)
{
if (!paused)
{
guid = Guid.NewGuid();
bytes = guid.ToByteArray();
++guidCount;
for (int i = 0; i < 16; i++)
{
var b = bytes[i];
++counts[b];
}
if (watch.Elapsed > reportInterval)
{
cursorPos.MoveCursor();
DumpFrequencies(counts, guidCount);
watch.Restart();
}
}
if (Console.KeyAvailable)
{
ProcessKey(Console.ReadKey());
}
}
}
static void ProcessKey(ConsoleKeyInfo keyInfo)
{
switch (keyInfo.Key)
{
case ConsoleKey.P:
paused = !paused;
break;
case ConsoleKey.X:
exit = true;
break;
}
}
static void DumpFrequencies(long[] byteCounts, long guidCount)
{
Write("\r\n{0} GUIDs generated. Frequencies:\r\n\r\n", guidCount);
const int itemWidth = 9;
int colCount = Console.WindowWidth / (itemWidth*2);
for (int i = 0; i < 256; i++)
{
var f = (double)byteCounts[i] / (16 * guidCount);
Write(RightAdjust(itemWidth, "{0:x}", i));
Write(GetFrequencyColor(f), " {0:p}".PadRight(itemWidth), f);
if ((i + 1) % colCount == 0) Write("\r\n");
}
}
static ConsoleColor GetFrequencyColor(double f)
{
if (f < 0.003) return ConsoleColor.DarkRed;
if (f < 0.004) return ConsoleColor.Green;
if (f < 0.005) return ConsoleColor.Yellow;
return ConsoleColor.White;
}
static string RightAdjust(int w, string s, params object[] args)
{
if (args.Length > 0)
s = string.Format(s, args);
return s.PadLeft(w);
}
#region From my library, so I need not include that here...
class CursorLocation
{
public int X, Y;
public CursorLocation()
{
X = Console.CursorLeft;
Y = Console.CursorTop;
}
public void MoveCursor()
{
Console.CursorLeft = X;
Console.CursorTop = Y;
}
}
static public void Write(string s, params object[] args)
{
if (args.Length > 0) s = string.Format(s, args);
Console.Write(s);
}
static public void Write(ConsoleColor c, string s, params object[] args)
{
var old = Console.ForegroundColor;
Console.ForegroundColor = c;
Write(s, args);
Console.ForegroundColor = old;
}
static public void WriteNewline(int count = 1)
{
while (count-- > 0) Console.WriteLine();
}
static public void WriteLine(string s, params object[] args)
{
Write(s, args);
Console.Write(Environment.NewLine);
}
static public void WriteLine(ConsoleColor c, string s, params object[] args)
{
Write(c, s, args);
Console.Write(Environment.NewLine);
}
#endregion
}
}
>
. Stackoverflow grrr-eat.