# Random.NextDoubleRandom.NextDoubleRandom.NextDoubleRandom.NextDouble Method

## Definition

Gibt eine zufällige Gleitkommazahl zurück, die größer oder gleich 0,0 und kleiner als 1,0 ist.Returns a random floating-point number that is greater than or equal to 0.0, and less than 1.0.

``````public:
virtual double NextDouble();``````
``public virtual double NextDouble ();``
``````abstract member NextDouble : unit -> double
override this.NextDouble : unit -> double``````
``Public Overridable Function NextDouble () As Double``

#### Gibt zurück

Eine Gleitkommazahl mit doppelter Genauigkeit, die größer oder gleich 0,0 und kleiner als 1,0 ist.A double-precision floating point number that is greater than or equal to 0.0, and less than 1.0.

## Beispiele

Im folgenden Beispiel wird die NextDouble -Methode verwendet, um Sequenzen zufälliger Double-Werte zu generieren.The following example uses the NextDouble method to generate sequences of random doubles.

``````// 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 the following output.

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 the following output.

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 the following output.
'
' 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
``````

Im folgenden Beispiel wird die NextDouble -Methode aufgerufen, um 100 Zufallszahlen zu generieren und deren Häufigkeitsverteilung anzeigt.The following example calls the NextDouble method to generate 100 random numbers and displays their frequency distribution.

``````int[] frequency = new int[10];
double number;
Random rnd = new Random();

for (int ctr = 0; ctr <= 99; ctr++) {
number = rnd.NextDouble();
frequency[(int) Math.Floor(number*10)] ++;
}
Console.WriteLine("Distribution of Random Numbers:");
for (int ctr = frequency.GetLowerBound(0); ctr <= frequency.GetUpperBound(0); ctr++)
Console.WriteLine("0.{0}0-0.{0}9       {1}", ctr, frequency[ctr]);

// The following example displays output similar to the following:
//       Distribution of Random Numbers:
//       0.00-0.09       16
//       0.10-0.19       8
//       0.20-0.29       8
//       0.30-0.39       11
//       0.40-0.49       9
//       0.50-0.59       6
//       0.60-0.69       13
//       0.70-0.79       6
//       0.80-0.89       9
//       0.90-0.99       14
``````
``````Module Example
Public Sub Main()
Dim frequency(9) As Integer
Dim number As Double
Dim rnd As New Random()

For ctr As Integer = 0 To 99
number = rnd.NextDouble()
frequency(CInt(Math.Floor(number*10))) += 1
Next
Console.WriteLine("Distribution of Random Numbers:")
For ctr As Integer = frequency.GetLowerBound(0) To frequency.GetUpperBound(0)
Console.WriteLine("0.{0}0-0.{0}9       {1}", ctr, frequency(ctr))
Next
End Sub
End Module
' The following example displays output similar to the following:
'       Distribution of Random Numbers:
'       0.00-0.09       16
'       0.10-0.19       8
'       0.20-0.29       8
'       0.30-0.39       11
'       0.40-0.49       9
'       0.50-0.59       6
'       0.60-0.69       13
'       0.70-0.79       6
'       0.80-0.89       9
'       0.90-0.99       14
``````

## Hinweise

Die tatsächliche obere Grenze der Zufallszahl, die von dieser Methode zurückgegeben wird, ist 0.99999999999999978.The actual upper bound of the random number returned by this method is 0.99999999999999978.

Informationen zum Abrufen von zufälligen Gleit Komma Werten in einem anderen Bereich als 0,0 und 1,0 finden Sie im Abschnitt Random "Abrufen von Gleit Komma Werten in einem angegebenen Bereich" im Thema zur-Klasse.To retrieve random floating-point values within a range other than 0.0 and 1.0, see the "Retrieve floating-point values in a specified range" section of the Random class topic.

Bei dieser Methode handelt es sich um die öffentliche Version der Samplegeschützten Methode.This method is the public version of the protected method, Sample.