# Random 建構函式

## 多載

 Random() 使用預設種子值初始化 Random 類別的新執行個體。 Random(Int32) 使用指定的種子值，初始化 Random 類別的新執行個體。

## Random()

``````public:
Random();``````
``public Random ();``
``Public Sub New ()``

### 範例

``````using System;

public class RandomNumbers
{
public static void Main()
{
Random rand1 = new Random();
Random rand2 = new Random();
Random rand3 = new Random();
ShowRandomNumbers(rand1);
ShowRandomNumbers(rand2);
ShowRandomNumbers(rand3);
}

private static void ShowRandomNumbers(Random rand)
{
Console.WriteLine();
byte[] values = new byte[5];
rand.NextBytes(values);
foreach (byte value in values)
Console.Write("{0, 5}", value);
Console.WriteLine();
}
}
// The example displays an output similar to the following:
//       28   35  133  224   58
//
//       28   35  133  224   58
//
//       32  222   43  251   49
``````
``````open System

let showRandomNumbers (rand: Random) =
printfn ""
let values = Array.zeroCreate 5
rand.NextBytes values
for value in values do
printf "%5i" value
printfn ""

let rand1 = Random()
let rand2 = Random()
let rand3 = Random()

showRandomNumbers rand1
showRandomNumbers rand2
showRandomNumbers rand3

// The example displays an output similar to the following:
//       28   35  133  224   58
//
//       28   35  133  224   58
//
//       32  222   43  251   49
``````
``````Imports System.Threading

Module RandomNumbers
Public Sub Main()
Dim rand1 As New Random()
Dim rand2 As New Random()
Dim rand3 As New Random()
ShowRandomNumbers(rand1)
ShowRandomNumbers(rand2)
ShowRandomNumbers(rand3)
End Sub

Private Sub ShowRandomNumbers(rand As Random)
Console.WriteLine()
Dim values(4) As Byte
rand.NextBytes(values)
For Each value As Byte In values
Console.Write("{0, 5}", value)
Next
Console.WriteLine()
End Sub
End Module
' The example displays an output similar to the following:
'       28   35  133  224   58
'
'       28   35  133  224   58
'
'       32  222   43  251   49
``````

## Random(Int32)

``````public:
Random(int Seed);``````
``public Random (int Seed);``
``new Random : int -> Random``
``Public Sub New (Seed As Integer)``

Seed
Int32

### 範例

``````// Example of the Random class constructors and Random::NextDouble()
// method.
using namespace System;

// Generate random numbers from the specified Random object.
void RunIntNDoubleRandoms(Random^ randObj)
{

// Generate the first six random integers.
for (int j = 0; j < 6; j++)
Console::Write(" {0,10} ", randObj->Next());
Console::WriteLine();

// Generate the first six random doubles.
for (int j = 0; j < 6; j++)
Console::Write(" {0:F8} ", randObj->NextDouble());
Console::WriteLine();
}

// Create a Random object with the specified seed.
void FixedSeedRandoms(int seed)
{
Console::WriteLine("\nRandom numbers from a Random object with seed = {0}:", seed);
Random^ fixRand = gcnew Random(seed);
RunIntNDoubleRandoms(fixRand);
}

// Create a random object with a timer-generated seed.
void AutoSeedRandoms()
{

// Wait to allow the timer to advance.
Console::WriteLine("\nRandom numbers from a Random object "
"with an auto-generated seed:");
Random^ autoRand = gcnew Random;
RunIntNDoubleRandoms(autoRand);
}

int main()
{
Console::WriteLine("This example of the Random class constructors and Random"
"::NextDouble() \ngenerates the following output.\n");
Console::WriteLine("Create Random objects, and then generate and "
"display six integers and \nsix doubles from each.");
FixedSeedRandoms(123);
FixedSeedRandoms(123);
FixedSeedRandoms(456);
FixedSeedRandoms(456);
AutoSeedRandoms();
AutoSeedRandoms();
AutoSeedRandoms();
}

/*
This example of the Random class constructors and Random::NextDouble()
generates an output similar to the following:

Create Random objects, and then generate and display six integers and
six doubles from each.

Random numbers from a Random object with seed = 123:
2114319875  1949518561  1596751841  1742987178  1586516133   103755708
0.01700087  0.14935942  0.19470390  0.63008947  0.90976122  0.49519146

Random numbers from a Random object with seed = 123:
2114319875  1949518561  1596751841  1742987178  1586516133   103755708
0.01700087  0.14935942  0.19470390  0.63008947  0.90976122  0.49519146

Random numbers from a Random object with seed = 456:
2044805024  1323311594  1087799997  1907260840   179380355   120870348
0.21988117  0.21026556  0.39236514  0.42420498  0.24102703  0.47310170

Random numbers from a Random object with seed = 456:
2044805024  1323311594  1087799997  1907260840   179380355   120870348
0.21988117  0.21026556  0.39236514  0.42420498  0.24102703  0.47310170

Random numbers from a Random object with an auto-generated seed:
1624372556  1894939458   302472229   588108304    23919954  1085111949
0.14595512  0.30162298  0.92267372  0.55707657  0.25430079  0.74143239

Random numbers from a Random object with an auto-generated seed:
2105952511  1753605347   280739490   876793040  1129567796   524571616
0.62652210  0.31846701  0.15984073  0.24458755  0.62160607  0.54857684

Random numbers from a Random object with an auto-generated seed:
440048819  1612271236   259006751  1165477776    87731991  2111514930
0.10708907  0.33531104  0.39700773  0.93209853  0.98891135  0.35572129
*/
``````
``````// Example of the Random class constructors and Random.NextDouble()
// method.
using System;

public class RandomObjectDemo
{
// Generate random numbers from the specified Random object.
static void RunIntNDoubleRandoms(Random randObj)
{
// Generate the first six random integers.
for(int j = 0; j < 6; j++)
Console.Write(" {0,10} ", randObj.Next());
Console.WriteLine();

// Generate the first six random doubles.
for(int j = 0; j < 6; j++)
Console.Write(" {0:F8} ", randObj.NextDouble());
Console.WriteLine();
}

// Create a Random object with the specified seed.
static void FixedSeedRandoms(int seed)
{
Console.WriteLine(
"\nRandom numbers from a Random object with " +
"seed = {0}:", seed);
Random fixRand = new Random(seed);

RunIntNDoubleRandoms(fixRand);
}

// Create a random object with a timer-generated seed.
static void AutoSeedRandoms()
{
// Wait to allow the timer to advance.

Console.WriteLine(
"\nRandom numbers from a Random object " +
"with an auto-generated seed:");
Random autoRand = new Random();

RunIntNDoubleRandoms(autoRand);
}

static void Main()
{
Console.WriteLine(
"This example of the Random class constructors and " +
"Random.NextDouble() \n" +
"generates the following output.\n");
Console.WriteLine(
"Create Random objects, and then generate and " +
"display six integers and \nsix doubles from each.");

FixedSeedRandoms(123);
FixedSeedRandoms(123);

FixedSeedRandoms(456);
FixedSeedRandoms(456);

AutoSeedRandoms();
AutoSeedRandoms();
AutoSeedRandoms();
}
}

/*
This example of the Random class constructors and Random.NextDouble()
generates an output similar to the following:

Create Random objects, and then generate and display six integers and
six doubles from each.

Random numbers from a Random object with seed = 123:
2114319875  1949518561  1596751841  1742987178  1586516133   103755708
0.01700087  0.14935942  0.19470390  0.63008947  0.90976122  0.49519146

Random numbers from a Random object with seed = 123:
2114319875  1949518561  1596751841  1742987178  1586516133   103755708
0.01700087  0.14935942  0.19470390  0.63008947  0.90976122  0.49519146

Random numbers from a Random object with seed = 456:
2044805024  1323311594  1087799997  1907260840   179380355   120870348
0.21988117  0.21026556  0.39236514  0.42420498  0.24102703  0.47310170

Random numbers from a Random object with seed = 456:
2044805024  1323311594  1087799997  1907260840   179380355   120870348
0.21988117  0.21026556  0.39236514  0.42420498  0.24102703  0.47310170

Random numbers from a Random object with an auto-generated seed:
380213349   127379247  1969091178  1983029819  1963098450  1648433124
0.08824121  0.41249688  0.36445811  0.05637512  0.62702451  0.49595560

Random numbers from a Random object with an auto-generated seed:
861793304  2133528783  1947358439   124230908   921262645  1087892791
0.56880819  0.42934091  0.60162512  0.74388610  0.99432979  0.30310005

Random numbers from a Random object with an auto-generated seed:
1343373259  1992194672  1925625700   412915644  2026910487   527352458
0.04937517  0.44618494  0.83879212  0.43139707  0.36163507  0.11024451
*/
``````
``````// Example of the Random class constructors and Random.NextDouble()
// method.
open System

// Generate random numbers from the specified Random object.
let runIntNDoubleRandoms (randObj: Random) =
// Generate the first six random integers.
for _ = 1 to 6 do
printf \$" {randObj.Next(),10} "
printfn ""

// Generate the first six random doubles.
for _ = 1 to 6 do
printf \$" {randObj.NextDouble():F8} "
printfn ""

let fixedSeedRandoms seed =
printfn \$"\nRandom numbers from a Random object with seed = %i{seed}:"
let fixRand = Random seed

runIntNDoubleRandoms fixRand

let autoSeedRandoms () =
// Wait to allow the timer to advance.

printfn "\nRandom numbers from a Random object with an auto-generated seed: "
let autoRand = Random ()

runIntNDoubleRandoms autoRand

printfn
"""This example of the Random class constructors and Random.NextDouble()
generates the following output.
Create Random objects, and then generate and display six integers and
six doubles from each."""

fixedSeedRandoms 123
fixedSeedRandoms 123

fixedSeedRandoms 456
fixedSeedRandoms 456

autoSeedRandoms ()
autoSeedRandoms ()
autoSeedRandoms ()

(*
This example of the Random class constructors and Random.NextDouble()
generates an output similar to the following:

Create Random objects, and then generate and display six integers and
six doubles from each.

Random numbers from a Random object with seed = 123:
2114319875  1949518561  1596751841  1742987178  1586516133   103755708
0.01700087  0.14935942  0.19470390  0.63008947  0.90976122  0.49519146

Random numbers from a Random object with seed = 123:
2114319875  1949518561  1596751841  1742987178  1586516133   103755708
0.01700087  0.14935942  0.19470390  0.63008947  0.90976122  0.49519146

Random numbers from a Random object with seed = 456:
2044805024  1323311594  1087799997  1907260840   179380355   120870348
0.21988117  0.21026556  0.39236514  0.42420498  0.24102703  0.47310170

Random numbers from a Random object with seed = 456:
2044805024  1323311594  1087799997  1907260840   179380355   120870348
0.21988117  0.21026556  0.39236514  0.42420498  0.24102703  0.47310170

Random numbers from a Random object with an auto-generated seed:
380213349   127379247  1969091178  1983029819  1963098450  1648433124
0.08824121  0.41249688  0.36445811  0.05637512  0.62702451  0.49595560

Random numbers from a Random object with an auto-generated seed:
861793304  2133528783  1947358439   124230908   921262645  1087892791
0.56880819  0.42934091  0.60162512  0.74388610  0.99432979  0.30310005

Random numbers from a Random object with an auto-generated seed:
1343373259  1992194672  1925625700   412915644  2026910487   527352458
0.04937517  0.44618494  0.83879212  0.43139707  0.36163507  0.11024451
*)
``````
``````' Example of the Random class constructors and Random.NextDouble()
' method.

Module RandomObjectDemo

' Generate random numbers from the specified Random object.
Sub RunIntNDoubleRandoms(randObj As Random)

' Generate the first six random integers.
Dim j As Integer
For j = 0 To 5
Console.Write(" {0,10} ", randObj.Next())
Next j
Console.WriteLine()

' Generate the first six random doubles.
For j = 0 To 5
Console.Write(" {0:F8} ", randObj.NextDouble())
Next j
Console.WriteLine()
End Sub

' Create a Random object with the specified seed.
Sub FixedSeedRandoms(seed As Integer)

Console.WriteLine(vbCrLf & _
"Random numbers from a Random object with " & _
"seed = {0}:", seed)
Dim fixRand As New Random(seed)

RunIntNDoubleRandoms(fixRand)
End Sub

' Create a random object with a timer-generated seed.
Sub AutoSeedRandoms()

' Wait to allow the timer to advance.

Console.WriteLine(vbCrLf & _
"Random numbers from a Random object " & _
"with an auto-generated seed:")
Dim autoRand As New Random()

RunIntNDoubleRandoms(autoRand)
End Sub

Sub Main()
Console.WriteLine(_
"This example of the Random class constructors " & _
"and Random.NextDouble() " & vbCrLf & _
"generates the following output." & vbCrLf)
Console.WriteLine("Create Random " & _
"objects, and then generate and display six " & _
"integers and " & vbCrLf & "six doubles from each.")

FixedSeedRandoms(123)
FixedSeedRandoms(123)

FixedSeedRandoms(456)
FixedSeedRandoms(456)

AutoSeedRandoms()
AutoSeedRandoms()
AutoSeedRandoms()
End Sub
End Module

' This example of the Random class constructors and Random.NextDouble()
' generates an output similar to the following:
'
' Create Random objects, and then generate and display six integers and
' six doubles from each.
'
' Random numbers from a Random object with seed = 123:
'  2114319875  1949518561  1596751841  1742987178  1586516133   103755708
'  0.01700087  0.14935942  0.19470390  0.63008947  0.90976122  0.49519146
'
' Random numbers from a Random object with seed = 123:
'  2114319875  1949518561  1596751841  1742987178  1586516133   103755708
'  0.01700087  0.14935942  0.19470390  0.63008947  0.90976122  0.49519146
'
' Random numbers from a Random object with seed = 456:
'  2044805024  1323311594  1087799997  1907260840   179380355   120870348
'  0.21988117  0.21026556  0.39236514  0.42420498  0.24102703  0.47310170
'
' Random numbers from a Random object with seed = 456:
'  2044805024  1323311594  1087799997  1907260840   179380355   120870348
'  0.21988117  0.21026556  0.39236514  0.42420498  0.24102703  0.47310170
'
' Random numbers from a Random object with an auto-generated seed:
'  1920831619  1346865774  2006582766  1968819760   332463652   110770792
'  0.71326689  0.50383335  0.50446082  0.66312569  0.94517193  0.58059287
'
' Random numbers from a Random object with an auto-generated seed:
'   254927927  1205531663  1984850027   110020849  1438111494  1697714106
'  0.19383387  0.52067738  0.74162783  0.35063667  0.31247720  0.38773733
'
' Random numbers from a Random object with an auto-generated seed:
'   736507882  1064197552  1963117288   398705585   396275689  1137173773
'  0.67440084  0.53752140  0.97879483  0.03814764  0.67978248  0.19488178
``````

### 備註

``````using System;

public class Example
{
public static void Main()
{
Random rand1 = new Random((int) DateTime.Now.Ticks & 0x0000FFFF);
Random rand2 = new Random((int) DateTime.Now.Ticks & 0x0000FFFF);
Random rand3 = new Random((int) DateTime.Now.Ticks & 0x0000FFFF);
ShowRandomNumbers(rand1);
ShowRandomNumbers(rand2);
ShowRandomNumbers(rand3);
}

private static void ShowRandomNumbers(Random rand)
{
Console.WriteLine();
byte[] values = new byte[4];
rand.NextBytes(values);
foreach (var value in values)
Console.Write("{0, 5}", value);

Console.WriteLine();
}
}
// The example displays output similar to the following:
//   145  214  177  134  173
//
//   145  214  177  134  173
//
//   126  185  175  249  157
``````
``````open System

let showRandomNumbers (rand: Random) =
printfn ""
let values = Array.zeroCreate 5
rand.NextBytes values
for value in values do
printf "%5i" value
printfn ""

let rand1 = Random(DateTime.Now.Ticks &&& 0x0000FFFFL |> int)
let rand2 = Random(DateTime.Now.Ticks &&& 0x0000FFFFL |> int)
let rand3 = Random(DateTime.Now.Ticks &&& 0x0000FFFFL |> int)

showRandomNumbers rand1
showRandomNumbers rand2
showRandomNumbers rand3

// The example displays output similar to the following:
//   145  214  177  134  173
//
//   145  214  177  134  173
//
//   126  185  175  249  157
``````
``````Imports System.Threading

Module RandomNumbers
Public Sub Main()
Dim rand1 As New Random(CInt(Date.Now.Ticks And &h0000FFFF))
Dim rand2 As New Random(CInt(Date.Now.Ticks And &h0000FFFF))
Dim rand3 As New Random(CInt(Date.Now.Ticks And &h0000FFFF))
ShowRandomNumbers(rand1)
ShowRandomNumbers(rand2)
ShowRandomNumbers(rand3)
End Sub

Private Sub ShowRandomNumbers(rand As Random)
Console.WriteLine()
Dim values(4) As Byte
rand.NextBytes(values)
For Each value As Byte In values
Console.Write("{0, 5}", value)
Next
Console.WriteLine()
End Sub
End Module
' The example displays output similar to the following:
'      145  214  177  134  173
'
'      145  214  177  134  173
'
'      126  185  175  249  157
``````