Random.Next 方法
定义
重要
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返回一个随机整数。
重载
| Next() |
返回一个非负随机整数。 |
| Next(Int32) |
返回一个小于所指定最大值的非负随机整数。 |
| Next(Int32, Int32) |
返回在指定范围内的任意整数。 |
Next()
- Source:
- Random.cs
- Source:
- Random.cs
- Source:
- Random.cs
返回一个非负随机整数。
public:
virtual int Next();public virtual int Next ();abstract member Next : unit -> int
override this.Next : unit -> intPublic Overridable Function Next () As Integer返回
大于或等于 0 且小于 Int32.MaxValue 的 32 位有符号整数。
示例
以下示例对 方法进行重复调用， Next 以生成用户请求的特定数量的随机数。 方法 Console.ReadLine 用于获取客户输入。
using namespace System;
void main()
{
Console::Write("Number of random numbers to generate: ");
String^ line = Console::ReadLine();
unsigned int numbers = 0;
Random^ rnd = gcnew Random();
if (! UInt32::TryParse(line, numbers))
numbers = 10;
for (unsigned int ctr = 1; ctr <= numbers; ctr++)
Console::WriteLine("{0,15:N0}", rnd->Next());
}
// The example displays output like the following when asked to generate
// 15 random numbers:
// Number of random numbers to generate: 15
// 1,733,189,596
// 566,518,090
// 1,166,108,546
// 1,931,426,514
// 1,341,108,291
// 1,012,698,049
// 890,578,409
// 1,377,589,722
// 2,108,384,181
// 1,532,939,448
// 762,207,767
// 815,074,920
// 1,521,208,785
// 1,950,436,671
// 1,266,596,666
Console.Write("Number of random numbers to generate: ");
string? line = Console.ReadLine();
Random rnd = new Random();
if (!int.TryParse(line, out int numbers) || numbers <= 0)
{
numbers = 10;
}
for (uint ctr = 1; ctr <= numbers; ctr++)
Console.WriteLine($"{rnd.Next(),15:N0}");
// The example displays output like the following when asked to generate
// 15 random numbers:
// Number of random numbers to generate: 15
// 367 920 603
// 1 143 790 667
// 1 360 963 275
// 1 851 697 775
// 248 956 796
// 1 009 615 458
// 1 617 743 155
// 1 821 609 652
// 1 661 761 949
// 477 300 794
// 288 418 129
// 425 371 492
// 1 558 147 880
// 1 473 704 017
// 777 507 489
let rnd = Random()
printfn "Generating 10 random numbers:"
for _ = 1 to 10 do
printfn $"{rnd.Next(),15:N0}"
// The example displays output like the following:
//
// Generating 10 random numbers:
// 1,733,189,596
// 566,518,090
// 1,166,108,546
// 1,931,426,514
// 1,532,939,448
// 762,207,767
// 815,074,920
// 1,521,208,785
// 1,950,436,671
// 1,266,596,666
Module Example
Public Sub Main()
Console.Write("Number of random numbers to generate: ")
Dim line As String = Console.ReadLine()
Dim numbers As UInteger = 0
Dim rnd As New Random()
If Not UInt32.TryParse(line, numbers) Then numbers = 10
For ctr As UInteger = 1 To numbers
Console.WriteLine("{0,15:N0}", rnd.Next())
Next
End Sub
End Module
' The example displays output like the following when asked to generate
' 15 random numbers:
' Number of random numbers to generate: 15
' 1,733,189,596
' 566,518,090
' 1,166,108,546
' 1,931,426,514
' 1,341,108,291
' 1,012,698,049
' 890,578,409
' 1,377,589,722
' 2,108,384,181
' 1,532,939,448
' 762,207,767
' 815,074,920
' 1,521,208,785
' 1,950,436,671
' 1,266,596,666
以下示例从 Random 派生类，以生成一个随机数序列，该序列的分布不同于基类 的 方法生成的 Sample 统一分布。 它替代 Sample 方法以提供随机数的分布，并重写 Random.Next 方法以使用随机数系列。
using namespace System;
// This derived class converts the uniformly distributed random
// numbers generated by base.Sample() to another distribution.
public ref class RandomProportional : Random
{
// The Sample method generates a distribution proportional to the value
// of the random numbers, in the range [0.0, 1.0].
protected:
virtual double Sample() override
{
return Math::Sqrt(Random::Sample());
}
public:
RandomProportional()
{}
virtual int Next() override
{
return (int) (Sample() * Int32::MaxValue);
}
};
int main(array<System::String ^> ^args)
{
const int rows = 4, cols = 6;
const int runCount = 1000000;
const int distGroupCount = 10;
const double intGroupSize =
((double) Int32::MaxValue + 1.0) / (double)distGroupCount;
RandomProportional ^randObj = gcnew RandomProportional();
array<int>^ intCounts = gcnew array<int>(distGroupCount);
array<int>^ realCounts = gcnew array<int>(distGroupCount);
Console::WriteLine(
"\nThe derived RandomProportional class overrides " +
"the Sample method to \ngenerate random numbers " +
"in the range [0.0, 1.0]. The distribution \nof " +
"the numbers is proportional to their numeric values. " +
"For example, \nnumbers are generated in the " +
"vicinity of 0.75 with three times the \n" +
"probability of those generated near 0.25.");
Console::WriteLine(
"\nRandom doubles generated with the NextDouble() " +
"method:\n");
// Generate and display [rows * cols] random doubles.
for (int i = 0; i < rows; i++)
{
for (int j = 0; j < cols; j++)
Console::Write("{0,12:F8}", randObj->NextDouble());
Console::WriteLine();
}
Console::WriteLine(
"\nRandom integers generated with the Next() " +
"method:\n");
// Generate and display [rows * cols] random integers.
for (int i = 0; i < rows; i++)
{
for (int j = 0; j < cols; j++)
Console::Write("{0,12}", randObj->Next());
Console::WriteLine();
}
Console::WriteLine(
"\nTo demonstrate the proportional distribution, " +
"{0:N0} random \nintegers and doubles are grouped " +
"into {1} equal value ranges. This \n" +
"is the count of values in each range:\n",
runCount, distGroupCount);
Console::WriteLine(
"{0,21}{1,10}{2,20}{3,10}", "Integer Range",
"Count", "Double Range", "Count");
Console::WriteLine(
"{0,21}{1,10}{2,20}{3,10}", "-------------",
"-----", "------------", "-----");
// Generate random integers and doubles, and then count
// them by group.
for (int i = 0; i < runCount; i++)
{
intCounts[ (int)((double)randObj->Next() /
intGroupSize) ]++;
realCounts[ (int)(randObj->NextDouble() *
(double)distGroupCount) ]++;
}
// Display the count of each group.
for (int i = 0; i < distGroupCount; i++)
Console::WriteLine(
"{0,10}-{1,10}{2,10:N0}{3,12:N5}-{4,7:N5}{5,10:N0}",
(int)((double)i * intGroupSize),
(int)((double)(i + 1) * intGroupSize - 1.0),
intCounts[ i ],
((double)i) / (double)distGroupCount,
((double)(i + 1)) / (double)distGroupCount,
realCounts[ i ]);
return 0;
}
/*
This example of Random.Sample() displays output similar to the following:
The derived RandomProportional class overrides the Sample method to
generate random numbers in the range [0.0, 1.0). The distribution
of the numbers is proportional to the number values. For example,
numbers are generated in the vicinity of 0.75 with three times the
probability of those generated near 0.25.
Random doubles generated with the NextDouble() method:
0.59455719 0.17589882 0.83134398 0.35795862 0.91467727 0.54022658
0.93716947 0.54817519 0.94685080 0.93705478 0.18582318 0.71272428
0.77708682 0.95386216 0.70412393 0.86099417 0.08275804 0.79108316
0.71019941 0.84205103 0.41685082 0.58186880 0.89492302 0.73067715
Random integers generated with the Next() method:
1570755704 1279192549 1747627711 1705700211 1372759203 1849655615
2046235980 1210843924 1554274149 1307936697 1480207570 1057595022
337854215 844109928 2028310798 1386669369 2073517658 1291729809
1537248240 1454198019 1934863511 1640004334 2032620207 534654791
To demonstrate the proportional distribution, 1,000,000 random
integers and doubles are grouped into 10 equal value ranges. This
is the count of values in each range:
Integer Range Count Double Range Count
------------- ----- ------------ -----
0- 214748363 10,079 0.00000-0.10000 10,148
214748364- 429496728 29,835 0.10000-0.20000 29,849
429496729- 644245093 49,753 0.20000-0.30000 49,948
644245094- 858993458 70,325 0.30000-0.40000 69,656
858993459-1073741823 89,906 0.40000-0.50000 90,337
1073741824-1288490187 109,868 0.50000-0.60000 110,225
1288490188-1503238552 130,388 0.60000-0.70000 129,986
1503238553-1717986917 149,231 0.70000-0.80000 150,428
1717986918-1932735282 170,234 0.80000-0.90000 169,610
1932735283-2147483647 190,381 0.90000-1.00000 189,813
*/
using System;
// This derived class converts the uniformly distributed random
// numbers generated by base.Sample() to another distribution.
public class RandomProportional : Random
{
// The Sample method generates a distribution proportional to the value
// of the random numbers, in the range [0.0, 1.0].
protected override double Sample()
{
return Math.Sqrt(base.Sample());
}
public override int Next()
{
return (int) (Sample() * int.MaxValue);
}
}
public class RandomSampleDemo
{
static void Main()
{
const int rows = 4, cols = 6;
const int runCount = 1000000;
const int distGroupCount = 10;
const double intGroupSize =
((double)int.MaxValue + 1.0) / (double)distGroupCount;
RandomProportional randObj = new RandomProportional();
int[ ] intCounts = new int[ distGroupCount ];
int[ ] realCounts = new int[ distGroupCount ];
Console.WriteLine(
"\nThe derived RandomProportional class overrides " +
"the Sample method to \ngenerate random numbers " +
"in the range [0.0, 1.0]. The distribution \nof " +
"the numbers is proportional to their numeric values. " +
"For example, \nnumbers are generated in the " +
"vicinity of 0.75 with three times the \n" +
"probability of those generated near 0.25.");
Console.WriteLine(
"\nRandom doubles generated with the NextDouble() " +
"method:\n");
// Generate and display [rows * cols] random doubles.
for (int i = 0; i < rows; i++)
{
for (int j = 0; j < cols; j++)
Console.Write("{0,12:F8}", randObj.NextDouble());
Console.WriteLine();
}
Console.WriteLine(
"\nRandom integers generated with the Next() " +
"method:\n");
// Generate and display [rows * cols] random integers.
for (int i = 0; i < rows; i++)
{
for (int j = 0; j < cols; j++)
Console.Write("{0,12}", randObj.Next());
Console.WriteLine();
}
Console.WriteLine(
"\nTo demonstrate the proportional distribution, " +
"{0:N0} random \nintegers and doubles are grouped " +
"into {1} equal value ranges. This \n" +
"is the count of values in each range:\n",
runCount, distGroupCount);
Console.WriteLine(
"{0,21}{1,10}{2,20}{3,10}", "Integer Range",
"Count", "Double Range", "Count");
Console.WriteLine(
"{0,21}{1,10}{2,20}{3,10}", "-------------",
"-----", "------------", "-----");
// Generate random integers and doubles, and then count
// them by group.
for (int i = 0; i < runCount; i++)
{
intCounts[ (int)((double)randObj.Next() /
intGroupSize) ]++;
realCounts[ (int)(randObj.NextDouble() *
(double)distGroupCount) ]++;
}
// Display the count of each group.
for (int i = 0; i < distGroupCount; i++)
Console.WriteLine(
"{0,10}-{1,10}{2,10:N0}{3,12:N5}-{4,7:N5}{5,10:N0}",
(int)((double)i * intGroupSize),
(int)((double)(i + 1) * intGroupSize - 1.0),
intCounts[ i ],
((double)i) / (double)distGroupCount,
((double)(i + 1)) / (double)distGroupCount,
realCounts[ i ]);
}
}
/*
This example of Random.Sample() displays output similar to the following:
The derived RandomProportional class overrides the Sample method to
generate random numbers in the range [0.0, 1.0). The distribution
of the numbers is proportional to the number values. For example,
numbers are generated in the vicinity of 0.75 with three times the
probability of those generated near 0.25.
Random doubles generated with the NextDouble() method:
0.59455719 0.17589882 0.83134398 0.35795862 0.91467727 0.54022658
0.93716947 0.54817519 0.94685080 0.93705478 0.18582318 0.71272428
0.77708682 0.95386216 0.70412393 0.86099417 0.08275804 0.79108316
0.71019941 0.84205103 0.41685082 0.58186880 0.89492302 0.73067715
Random integers generated with the Next() method:
1570755704 1279192549 1747627711 1705700211 1372759203 1849655615
2046235980 1210843924 1554274149 1307936697 1480207570 1057595022
337854215 844109928 2028310798 1386669369 2073517658 1291729809
1537248240 1454198019 1934863511 1640004334 2032620207 534654791
To demonstrate the proportional distribution, 1,000,000 random
integers and doubles are grouped into 10 equal value ranges. This
is the count of values in each range:
Integer Range Count Double Range Count
------------- ----- ------------ -----
0- 214748363 10,079 0.00000-0.10000 10,148
214748364- 429496728 29,835 0.10000-0.20000 29,849
429496729- 644245093 49,753 0.20000-0.30000 49,948
644245094- 858993458 70,325 0.30000-0.40000 69,656
858993459-1073741823 89,906 0.40000-0.50000 90,337
1073741824-1288490187 109,868 0.50000-0.60000 110,225
1288490188-1503238552 130,388 0.60000-0.70000 129,986
1503238553-1717986917 149,231 0.70000-0.80000 150,428
1717986918-1932735282 170,234 0.80000-0.90000 169,610
1932735283-2147483647 190,381 0.90000-1.00000 189,813
*/
' This derived class converts the uniformly distributed random
' numbers generated by base.Sample() to another distribution.
Public Class RandomProportional
Inherits Random
' The Sample method generates a distribution proportional to the value
' of the random numbers, in the range [0.0, 1.0].
Protected Overrides Function Sample() As Double
Return Math.Sqrt(MyBase.Sample())
End Function
Public Overrides Function [Next]() As Integer
Return Sample() * Integer.MaxValue
End Function
End Class
Module RandomSampleDemo
Sub Main()
Const rows As Integer = 4, cols As Integer = 6
Const runCount As Integer = 1000000
Const distGroupCount As Integer = 10
Const intGroupSize As Double = _
(CDbl(Integer.MaxValue) + 1.0) / _
CDbl(distGroupCount)
Dim randObj As New RandomProportional()
Dim intCounts(distGroupCount) As Integer
Dim realCounts(distGroupCount) As Integer
Dim i As Integer, j As Integer
Console.WriteLine(vbCrLf & _
"The derived RandomProportional class overrides " & _
"the Sample method to " & vbCrLf & _
"generate random numbers in the range " & _
"[0.0, 1.0]. The distribution " & vbCrLf & _
"of the numbers is proportional to their numeric " & _
"values. For example, " & vbCrLf & _
"numbers are generated in the vicinity of 0.75 " & _
"with three times " & vbCrLf & "the " & _
"probability of those generated near 0.25.")
Console.WriteLine(vbCrLf & _
"Random doubles generated with the NextDouble() " & _
"method:" & vbCrLf)
' Generate and display [rows * cols] random doubles.
For i = 0 To rows - 1
For j = 0 To cols - 1
Console.Write("{0,12:F8}", randObj.NextDouble())
Next j
Console.WriteLine()
Next i
Console.WriteLine(vbCrLf & _
"Random integers generated with the Next() " & _
"method:" & vbCrLf)
' Generate and display [rows * cols] random integers.
For i = 0 To rows - 1
For j = 0 To cols - 1
Console.Write("{0,12}", randObj.Next())
Next j
Console.WriteLine()
Next i
Console.WriteLine(vbCrLf & _
"To demonstrate the proportional distribution, " & _
"{0:N0} random " & vbCrLf & _
"integers and doubles are grouped into {1} " & _
"equal value ranges. This " & vbCrLf & _
"is the count of values in each range:" & vbCrLf, _
runCount, distGroupCount)
Console.WriteLine("{0,21}{1,10}{2,20}{3,10}", _
"Integer Range", "Count", "Double Range", "Count")
Console.WriteLine("{0,21}{1,10}{2,20}{3,10}", _
"-------------", "-----", "------------", "-----")
' Generate random integers and doubles, and then count
' them by group.
For i = 0 To runCount - 1
intCounts(Fix(CDbl(randObj.Next()) / _
intGroupSize)) += 1
realCounts(Fix(randObj.NextDouble() * _
CDbl(distGroupCount))) += 1
Next i
' Display the count of each group.
For i = 0 To distGroupCount - 1
Console.WriteLine( _
"{0,10}-{1,10}{2,10:N0}{3,12:N5}-{4,7:N5}{5,10:N0}", _
Fix(CDbl(i) * intGroupSize), _
Fix(CDbl(i + 1) * intGroupSize - 1.0), _
intCounts(i), _
CDbl(i) / CDbl(distGroupCount), _
CDbl(i + 1) / CDbl(distGroupCount), _
realCounts(i))
Next i
End Sub
End Module
' This example of Random.Sample() generates output similar to the following:
'
' The derived RandomProportional class overrides the Sample method to
' generate random numbers in the range [0.0, 1.0]. The distribution
' of the numbers is proportional to their numeric values. For example,
' numbers are generated in the vicinity of 0.75 with three times
' the probability of those generated near 0.25.
'
' Random doubles generated with the NextDouble() method:
'
' 0.28377004 0.75920598 0.33430371 0.66720626 0.97080243 0.27353772
' 0.17787962 0.54618410 0.08145080 0.56286100 0.99002910 0.64898614
' 0.27673277 0.99455281 0.93778966 0.76162002 0.70533771 0.44375798
' 0.55939883 0.87383136 0.66465779 0.77392566 0.42393411 0.82409159
'
' Random integers generated with the Next() method:
'
' 1364479914 1230312341 1657373812 1526222928 988564704 700078020
' 1801013705 1541517421 1146312560 338318389 1558995993 2027260859
' 884520932 1320070465 570200106 1027684711 943035246 2088689333
' 630809089 1705728475 2140787648 2097858166 1863010875 1386804198
'
' To demonstrate the proportional distribution, 1,000,000 random
' integers and doubles are grouped into 10 equal value ranges. This
' is the count of values in each range:
'
' Integer Range Count Double Range Count
' ------------- ----- ------------ -----
' 0- 214748363 9,892 0.00000-0.10000 9,928
' 214748364- 429496728 30,341 0.10000-0.20000 30,101
' 429496729- 644245093 49,958 0.20000-0.30000 49,964
' 644245094- 858993458 70,099 0.30000-0.40000 70,213
' 858993459-1073741823 90,801 0.40000-0.50000 89,553
' 1073741824-1288490187 109,699 0.50000-0.60000 109,427
' 1288490188-1503238552 129,438 0.60000-0.70000 130,339
' 1503238553-1717986917 149,886 0.70000-0.80000 150,000
' 1717986918-1932735282 170,338 0.80000-0.90000 170,128
' 1932735283-2147483647 189,548 0.90000-1.00000 190,347
注解
Random.Next 生成一个随机数，其值范围为 0 到小于 Int32.MaxValue。 若要生成值范围为 0 到某个其他正数的随机数，请使用 Random.Next(Int32) 方法重载。 若要在不同的范围内生成随机数，请使用 Random.Next(Int32, Int32) 方法重载。
继承者说明
从 .NET Framework 版本 2.0 开始，如果从 Random 派生类并重写 Sample() 方法，则方法的Sample()派生类实现提供的分布不会用于调用方法的Next()基类实现。 而是使用基 Random 类返回的统一分布。 此行为可提高 类的整体性能 Random 。 若要修改此行为以调用 Sample() 派生类中的 方法，还必须重写 Next() 方法。
另请参阅
适用于
Next(Int32)
- Source:
- Random.cs
- Source:
- Random.cs
- Source:
- Random.cs
返回一个小于所指定最大值的非负随机整数。
public:
virtual int Next(int maxValue);public virtual int Next (int maxValue);abstract member Next : int -> int
override this.Next : int -> intPublic Overridable Function Next (maxValue As Integer) As Integer参数
- maxValue
- Int32
要生成的随机数的上限（随机数不能取该上限值）。
maxValue 必须大于或等于 0。
返回
大于或等于零且小于 maxValue 的 32 位有符号整数，即：返回值的范围通常包括零但不包括 maxValue。 但是，如果 maxValue 等于 0，则返回 0。
例外
maxValue 小于 0。
示例
以下示例使用 方法的各种重载 Next 生成随机整数。
// Example of the Random::Next() methods.
using namespace System;
// Generate random numbers with no bounds specified.
void NoBoundsRandoms(int seed)
{
Console::WriteLine("\nRandom object, seed = {0}, no bounds:", seed);
Random^ randObj = gcnew Random(seed);
// Generate six random integers from 0 to int.MaxValue.
for (int j = 0; j < 6; j++)
Console::Write("{0,11} ", randObj->Next());
Console::WriteLine();
}
// Generate random numbers with an upper bound specified.
void UpperBoundRandoms(int seed, int upper)
{
Console::WriteLine("\nRandom object, seed = {0}, upper bound = {1}:", seed, upper);
Random^ randObj = gcnew Random(seed);
// Generate six random integers from 0 to the upper bound.
for (int j = 0; j < 6; j++)
Console::Write("{0,11} ", randObj->Next(upper));
Console::WriteLine();
}
// Generate random numbers with both bounds specified.
void BothBoundsRandoms(int seed, int lower, int upper)
{
Console::WriteLine("\nRandom object, seed = {0}, lower = {1}, upper = {2}:", seed, lower, upper);
Random^ randObj = gcnew Random(seed);
// Generate six random integers from the lower to
// upper bounds.
for (int j = 0; j < 6; j++)
Console::Write("{0,11} ", randObj->Next(lower, upper));
Console::WriteLine();
}
int main()
{
Console::WriteLine("This example of the Random::Next() methods\n"
"generates the following output.\n");
Console::WriteLine("Create Random objects all with the same seed and "
"generate\nsequences of numbers with different "
"bounds. Note the effect\nthat the various "
"combinations of bounds have on the sequences.");
NoBoundsRandoms(234);
UpperBoundRandoms(234, Int32::MaxValue);
UpperBoundRandoms(234, 2000000000);
UpperBoundRandoms(234, 200000000);
BothBoundsRandoms(234, 0, Int32::MaxValue);
BothBoundsRandoms(234, Int32::MinValue, Int32::MaxValue);
BothBoundsRandoms(234, -2000000000, 2000000000);
BothBoundsRandoms(234, -200000000, 200000000);
BothBoundsRandoms(234, -2000, 2000);
}
/*
This example of the Random::Next() methods
generates the following output.
Create Random objects all with the same seed and generate
sequences of numbers with different bounds. Note the effect
that the various combinations of bounds have on the sequences.
Random object, seed = 234, no bounds:
2091148258 1024955023 711273344 1081917183 1833298756 109460588
Random object, seed = 234, upper bound = 2147483647:
2091148258 1024955023 711273344 1081917183 1833298756 109460588
Random object, seed = 234, upper bound = 2000000000:
1947533580 954563751 662424922 1007613896 1707392518 101943116
Random object, seed = 234, upper bound = 200000000:
194753358 95456375 66242492 100761389 170739251 10194311
Random object, seed = 234, lower = 0, upper = 2147483647:
2091148258 1024955023 711273344 1081917183 1833298756 109460588
Random object, seed = 234, lower = -2147483648, upper = 2147483647:
2034812868 -97573602 -724936960 16350718 1519113864 -1928562472
Random object, seed = 234, lower = -2000000000, upper = 2000000000:
1895067160 -90872498 -675150156 15227793 1414785036 -1796113767
Random object, seed = 234, lower = -200000000, upper = 200000000:
189506716 -9087250 -67515016 1522779 141478503 -179611377
Random object, seed = 234, lower = -2000, upper = 2000:
1895 -91 -676 15 1414 -1797
*/
Console.WriteLine(
"""
This example of the Random.Next() methods
generates the following output.
"""
);
Console.WriteLine(
"""
Create Random objects all with the same seed and
generate\nsequences of numbers with different
bounds. Note the effect\nthat the various
combinations of bounds have on the sequences.
"""
);
NoBoundsRandoms(234);
UpperBoundRandoms(234, int.MaxValue);
UpperBoundRandoms(234, 2000000000);
UpperBoundRandoms(234, 200000000);
BothBoundsRandoms(234, 0, int.MaxValue);
BothBoundsRandoms(234, int.MinValue, int.MaxValue);
BothBoundsRandoms(234, -2000000000, 2000000000);
BothBoundsRandoms(234, -200000000, 200000000);
BothBoundsRandoms(234, -2000, 2000);
// Generate random numbers with no bounds specified.
void NoBoundsRandoms(int seed)
{
Console.WriteLine(
$"\nRandom object, seed = {seed}, no bounds:"
);
Random randObj = new(seed);
// Generate six random integers from 0 to int.MaxValue.
for (int j = 0; j < 6; j++)
Console.Write($"{randObj.Next(),11} ");
Console.WriteLine();
}
// Generate random numbers with an upper bound specified.
void UpperBoundRandoms(int seed, int upper)
{
Console.WriteLine(
$"\nRandom object, seed = {seed}, upper bound = {upper}:"
);
Random randObj = new(seed);
// Generate six random integers from 0 to the upper bound.
for (int j = 0; j < 6; j++)
Console.Write($"{randObj.Next(upper),11} ");
Console.WriteLine();
}
// Generate random numbers with both bounds specified.
void BothBoundsRandoms(int seed, int lower, int upper)
{
Console.WriteLine(
"\nRandom object, seed = {0}, lower = {1}, " +
"upper = {2}:", seed, lower, upper);
Random randObj = new(seed);
// Generate six random integers from the lower to
// upper bounds.
for (int j = 0; j < 6; j++)
Console.Write($"{randObj.Next(lower, upper),11} ");
Console.WriteLine();
}
/*
This example of the Random.Next() methods
generates the following output.
Create Random objects all with the same seed and generate
sequences of numbers with different bounds. Note the effect
that the various combinations of bounds have on the sequences.
Random object, seed = 234, no bounds:
2091148258 1024955023 711273344 1081917183 1833298756 109460588
Random object, seed = 234, upper bound = 2147483647:
2091148258 1024955023 711273344 1081917183 1833298756 109460588
Random object, seed = 234, upper bound = 2000000000:
1947533580 954563751 662424922 1007613896 1707392518 101943116
Random object, seed = 234, upper bound = 200000000:
194753358 95456375 66242492 100761389 170739251 10194311
Random object, seed = 234, lower = 0, upper = 2147483647:
2091148258 1024955023 711273344 1081917183 1833298756 109460588
Random object, seed = 234, lower = -2147483648, upper = 2147483647:
2034812868 -97573602 -724936960 16350718 1519113864 -1928562472
Random object, seed = 234, lower = -2000000000, upper = 2000000000:
1895067160 -90872498 -675150156 15227793 1414785036 -1796113767
Random object, seed = 234, lower = -200000000, upper = 200000000:
189506716 -9087250 -67515016 1522779 141478503 -179611377
Random object, seed = 234, lower = -2000, upper = 2000:
1895 -91 -676 15 1414 -1797
*/
let noBoundsRandoms seed =
printfn "\nRandom object, seed = %i, no bounds:" seed
let randObj = Random seed
// Generate six random integers from 0 to int.MaxValue.
for _ = 1 to 6 do
printf $"%11i{randObj.Next()} "
printfn ""
// Generate random numbers with an upper bound specified.
let upperBoundRandoms seed upper =
printfn $"\nRandom object, seed = %i{seed}, upper bound = %i{upper}"
let randObj = Random seed
// Generate six random integers from 0 to the upper bound.
for _ = 1 to 6 do
printf $"%11i{randObj.Next upper} "
printfn ""
// Generate random numbers with both bounds specified.
let bothBoundRandoms seed lower upper =
printfn $"\nRandom object, seed = %i{seed}, lower = %i{lower}, upper = %i{upper}: "
let randObj = Random seed
// Generate six random integers from the lower to upper bounds.
for _ = 1 to 6 do
printf $"%11i{randObj.Next(lower,upper)} "
printfn ""
printfn "This example of the Random.Next() methods\ngenerates the following.\n"
printfn """Create Random objects all with the same seed and generate
sequences of numbers with different bounds. Note the effect
that the various combinations of bounds have on the sequences."""
noBoundsRandoms 234
upperBoundRandoms 234 Int32.MaxValue
upperBoundRandoms 234 2000000000
upperBoundRandoms 234 200000000
bothBoundRandoms 234 0 Int32.MaxValue
bothBoundRandoms 234 Int32.MinValue Int32.MaxValue
bothBoundRandoms 234 -2000000000 2000000000
bothBoundRandoms 234 -200000000 200000000
bothBoundRandoms 234 -2000 2000
(*
This example of the Random.Next() methods
generates the following output.
Create Random objects all with the same seed and generate
sequences of numbers with different bounds. Note the effect
that the various combinations of bounds have on the sequences.
Random object, seed = 234, no bounds:
2091148258 1024955023 711273344 1081917183 1833298756 109460588
Random object, seed = 234, upper bound = 2147483647:
2091148258 1024955023 711273344 1081917183 1833298756 109460588
Random object, seed = 234, upper bound = 2000000000:
1947533580 954563751 662424922 1007613896 1707392518 101943116
Random object, seed = 234, upper bound = 200000000:
194753358 95456375 66242492 100761389 170739251 10194311
Random object, seed = 234, lower = 0, upper = 2147483647:
2091148258 1024955023 711273344 1081917183 1833298756 109460588
Random object, seed = 234, lower = -2147483648, upper = 2147483647:
2034812868 -97573602 -724936960 16350718 1519113864 -1928562472
Random object, seed = 234, lower = -2000000000, upper = 2000000000:
1895067160 -90872498 -675150156 15227793 1414785036 -1796113767
Random object, seed = 234, lower = -200000000, upper = 200000000:
189506716 -9087250 -67515016 1522779 141478503 -179611377
Random object, seed = 234, lower = -2000, upper = 2000:
1895 -91 -676 15 1414 -1797
*)
' Example of the Random.Next() methods.
Module RandomNextDemo
' Generate random numbers with no bounds specified.
Sub NoBoundsRandoms(seed As Integer)
Console.WriteLine(vbCrLf &
"Random object, seed = {0}, no bounds:", seed)
Dim randObj As New Random(seed)
' Generate six random integers from 0 to int.MaxValue.
Dim j As Integer
For j = 0 To 5
Console.Write("{0,11} ", randObj.Next())
Next j
Console.WriteLine()
End Sub
' Generate random numbers with an upper bound specified.
Sub UpperBoundRandoms(seed As Integer, upper As Integer)
Console.WriteLine(vbCrLf &
"Random object, seed = {0}, upper bound = {1}:",
seed, upper)
Dim randObj As New Random(seed)
' Generate six random integers from 0 to the upper bound.
Dim j As Integer
For j = 0 To 5
Console.Write("{0,11} ", randObj.Next(upper))
Next j
Console.WriteLine()
End Sub
' Generate random numbers with both bounds specified.
Sub BothBoundsRandoms(seed As Integer, lower As Integer, upper As Integer)
Console.WriteLine(vbCrLf &
"Random object, seed = {0}, lower = {1}, " &
"upper = {2}:", seed, lower, upper)
Dim randObj As New Random(seed)
' Generate six random integers from the lower to
' upper bounds.
Dim j As Integer
For j = 0 To 5
Console.Write("{0,11} ",
randObj.Next(lower, upper))
Next j
Console.WriteLine()
End Sub
Sub Main()
Console.WriteLine(
"This example of the Random.Next() methods" &
vbCrLf & "generates the following output." & vbCrLf)
Console.WriteLine(
"Create Random objects all with the same seed " &
"and generate" & vbCrLf & "sequences of numbers " &
"with different bounds. Note the effect " & vbCrLf &
"that the various combinations " &
"of bounds have on the sequences.")
NoBoundsRandoms(234)
UpperBoundRandoms(234, Int32.MaxValue)
UpperBoundRandoms(234, 2000000000)
UpperBoundRandoms(234, 200000000)
BothBoundsRandoms(234, 0, Int32.MaxValue)
BothBoundsRandoms(234, Int32.MinValue, Int32.MaxValue)
BothBoundsRandoms(234, -2000000000, 2000000000)
BothBoundsRandoms(234, -200000000, 200000000)
BothBoundsRandoms(234, -2000, 2000)
End Sub
End Module
' This example of the Random.Next() methods
' generates the following output.
'
' Create Random objects all with the same seed and generate
' sequences of numbers with different bounds. Note the effect
' that the various combinations of bounds have on the sequences.
'
' Random object, seed = 234, no bounds:
' 2091148258 1024955023 711273344 1081917183 1833298756 109460588
'
' Random object, seed = 234, upper bound = 2147483647:
' 2091148258 1024955023 711273344 1081917183 1833298756 109460588
'
' Random object, seed = 234, upper bound = 2000000000:
' 1947533580 954563751 662424922 1007613896 1707392518 101943116
'
' Random object, seed = 234, upper bound = 200000000:
' 194753358 95456375 66242492 100761389 170739251 10194311
'
' Random object, seed = 234, lower = 0, upper = 2147483647:
' 2091148258 1024955023 711273344 1081917183 1833298756 109460588
'
' Random object, seed = 234, lower = -2147483648, upper = 2147483647:
' 2034812868 -97573602 -724936960 16350718 1519113864 -1928562472
'
' Random object, seed = 234, lower = -2000000000, upper = 2000000000:
' 1895067160 -90872498 -675150156 15227793 1414785036 -1796113767
'
' Random object, seed = 234, lower = -200000000, upper = 200000000:
' 189506716 -9087250 -67515016 1522779 141478503 -179611377
'
' Random object, seed = 234, lower = -2000, upper = 2000:
' 1895 -91 -676 15 1414 -1797
以下示例生成一个随机整数，该整数用作索引从数组中检索字符串值。 由于数组的最高索引小于其长度的 1，因此 属性的值 Array.Length 作为 maxValue 参数提供。
using namespace System;
void main()
{
Random^ rnd = gcnew Random();
array<String^>^ malePetNames = { "Rufus", "Bear", "Dakota", "Fido",
"Vanya", "Samuel", "Koani", "Volodya",
"Prince", "Yiska" };
array<String^>^ femalePetNames = { "Maggie", "Penny", "Saya", "Princess",
"Abby", "Laila", "Sadie", "Olivia",
"Starlight", "Talla" };
// Generate random indexes for pet names.
int mIndex = rnd->Next(malePetNames->Length);
int fIndex = rnd->Next(femalePetNames->Length);
// Display the result.
Console::WriteLine("Suggested pet name of the day: ");
Console::WriteLine(" For a male: {0}", malePetNames[mIndex]);
Console::WriteLine(" For a female: {0}", femalePetNames[fIndex]);
}
// The example displays output similar to the following:
// Suggested pet name of the day:
// For a male: Koani
// For a female: Maggie
Random rnd = new();
string[] malePetNames = [ "Rufus", "Bear", "Dakota", "Fido",
"Vanya", "Samuel", "Koani", "Volodya",
"Prince", "Yiska" ];
string[] femalePetNames = [ "Maggie", "Penny", "Saya", "Princess",
"Abby", "Laila", "Sadie", "Olivia",
"Starlight", "Talla" ];
// Generate random indexes for pet names.
int mIndex = rnd.Next(malePetNames.Length);
int fIndex = rnd.Next(femalePetNames.Length);
// Display the result.
Console.WriteLine("Suggested pet name of the day: ");
Console.WriteLine($" For a male: {malePetNames[mIndex]}");
Console.WriteLine($" For a female: {femalePetNames[fIndex]}");
// The example displays output similar to the following:
// Suggested pet name of the day:
// For a male: Koani
// For a female: Maggie
let rnd = Random()
let malePetNames =
[| "Rufus"; "Bear"; "Dakota"; "Fido";
"Vanya"; "Samuel"; "Koani"; "Volodya";
"Prince"; "Yiska" |]
let femalePetNames =
[| "Maggie"; "Penny"; "Saya"; "Princess";
"Abby"; "Laila"; "Sadie"; "Olivia";
"Starlight"; "Talla" |]
// Generate random indexes for pet names.
let mIndex = rnd.Next malePetNames.Length
let fIndex = rnd.Next femalePetNames.Length
// Display the result.
printfn "Suggested pet name of the day: "
printfn " For a male: %s" malePetNames.[mIndex]
printfn " For a female: %s" femalePetNames.[fIndex]
// The example displays output similar to the following:
// Suggested pet name of the day:
// For a male: Koani
// For a female: Maggie
Module Example
Public Sub Main()
Dim rnd As New Random()
Dim malePetNames() As String = { "Rufus", "Bear", "Dakota", "Fido",
"Vanya", "Samuel", "Koani", "Volodya",
"Prince", "Yiska" }
Dim femalePetNames() As String = { "Maggie", "Penny", "Saya", "Princess",
"Abby", "Laila", "Sadie", "Olivia",
"Starlight", "Talla" }
' Generate random indexes for pet names.
Dim mIndex As Integer = rnd.Next(malePetNames.Length)
Dim fIndex As Integer = rnd.Next(femalePetNames.Length)
' Display the result.
Console.WriteLine("Suggested pet name of the day: ")
Console.WriteLine(" For a male: {0}", malePetNames(mIndex))
Console.WriteLine(" For a female: {0}", femalePetNames(fIndex))
End Sub
End Module
' The example displays output similar to the following:
' Suggested pet name of the day:
' For a male: Koani
' For a female: Maggie
注解
重 Next(Int32) 载返回从 0 到 maxValue - 1 的随机整数。 但是，如果 maxValue 为 0，则方法返回 0。
另请参阅
适用于
Next(Int32, Int32)
- Source:
- Random.cs
- Source:
- Random.cs
- Source:
- Random.cs
返回在指定范围内的任意整数。
public:
virtual int Next(int minValue, int maxValue);public virtual int Next (int minValue, int maxValue);abstract member Next : int * int -> int
override this.Next : int * int -> intPublic Overridable Function Next (minValue As Integer, maxValue As Integer) As Integer参数
- minValue
- Int32
返回的随机数的下界（随机数可取该下界值）。
- maxValue
- Int32
返回的随机数的上界（随机数不能取该上界值）。
maxValue 必须大于或等于 minValue。
返回
一个大于等于 minValue 且小于 maxValue 的 32 位带符号整数，即：返回的值范围包括 minValue 但不包括 maxValue。 如果 minValue 等于 maxValue，则返回 minValue。
例外
minValue 大于 maxValue。
示例
以下示例使用 Random.Next(Int32, Int32) 方法生成具有三个不同范围的随机整数。 请注意，此示例的确切输出取决于传递给 Random 类构造函数的系统提供的种子值。
using namespace System;
void main()
{
Random^ rnd = gcnew Random();
Console::WriteLine("\n20 random integers from -100 to 100:");
for (int ctr = 1; ctr <= 20; ctr++)
{
Console::Write("{0,6}", rnd->Next(-100, 101));
if (ctr % 5 == 0) Console::WriteLine();
}
Console::WriteLine("\n20 random integers from 1000 to 10000:");
for (int ctr = 1; ctr <= 20; ctr++)
{
Console::Write("{0,8}", rnd->Next(1000, 10001));
if (ctr % 5 == 0) Console::WriteLine();
}
Console::WriteLine("\n20 random integers from 1 to 10:");
for (int ctr = 1; ctr <= 20; ctr++)
{
Console::Write("{0,6}", rnd->Next(1, 11));
if (ctr % 5 == 0) Console::WriteLine();
}
}
// The example displays output similar to the following:
// 20 random integers from -100 to 100:
// 65 -95 -10 90 -35
// -83 -16 -15 -19 41
// -67 -93 40 12 62
// -80 -95 67 -81 -21
//
// 20 random integers from 1000 to 10000:
// 4857 9897 4405 6606 1277
// 9238 9113 5151 8710 1187
// 2728 9746 1719 3837 3736
// 8191 6819 4923 2416 3028
//
// 20 random integers from 1 to 10:
// 9 8 5 9 9
// 9 1 2 3 8
// 1 4 8 10 5
// 9 7 9 10 5
Random rnd = new();
Console.WriteLine("\n20 random integers from -100 to 100:");
for (int ctr = 1; ctr <= 20; ctr++)
{
Console.Write("{0,6}", rnd.Next(-100, 101));
if (ctr % 5 == 0) Console.WriteLine();
}
Console.WriteLine("\n20 random integers from 1000 to 10000:");
for (int ctr = 1; ctr <= 20; ctr++)
{
Console.Write("{0,8}", rnd.Next(1000, 10001));
if (ctr % 5 == 0) Console.WriteLine();
}
Console.WriteLine("\n20 random integers from 1 to 10:");
for (int ctr = 1; ctr <= 20; ctr++)
{
Console.Write("{0,6}", rnd.Next(1, 11));
if (ctr % 5 == 0) Console.WriteLine();
}
// The example displays output similar to the following:
// 20 random integers from -100 to 100:
// 65 -95 -10 90 -35
// -83 -16 -15 -19 41
// -67 -93 40 12 62
// -80 -95 67 -81 -21
//
// 20 random integers from 1000 to 10000:
// 4857 9897 4405 6606 1277
// 9238 9113 5151 8710 1187
// 2728 9746 1719 3837 3736
// 8191 6819 4923 2416 3028
//
// 20 random integers from 1 to 10:
// 9 8 5 9 9
// 9 1 2 3 8
// 1 4 8 10 5
// 9 7 9 10 5
let rnd = Random()
printfn "\n20 random integers from -100 to 100:"
for i = 1 to 20 do
printf "%6i" (rnd.Next(-100,100))
if i % 5 = 0 then printfn ""
printfn "\n20 random integers from 1000 to 10000:"
for i = 1 to 20 do
printf "%8i" (rnd.Next(1000,10001))
if i % 5 = 0 then printfn ""
printfn "\n20 random integers from 1 to 10:"
for i = 1 to 20 do
printf "%6i" (rnd.Next(1,11))
if i % 5 = 0 then printfn ""
// The example displays output similar to the following:
// 20 random integers from -100 to 100:
// 65 -95 -10 90 -35
// -83 -16 -15 -19 41
// -67 -93 40 12 62
// -80 -95 67 -81 -21
//
// 20 random integers from 1000 to 10000:
// 4857 9897 4405 6606 1277
// 9238 9113 5151 8710 1187
// 2728 9746 1719 3837 3736
// 8191 6819 4923 2416 3028
//
// 20 random integers from 1 to 10:
// 9 8 5 9 9
// 9 1 2 3 8
// 1 4 8 10 5
// 9 7 9 10 5
Module Example
Public Sub Main()
Dim rnd As New Random()
Console.WriteLine("20 random integers from -100 to 100:")
For ctr As Integer = 1 To 20
Console.Write("{0,6}", rnd.Next(-100, 101))
If ctr Mod 5 = 0 Then Console.WriteLine()
Next
Console.WriteLine()
Console.WriteLine("20 random integers from 1000 to 10000:")
For ctr As Integer = 1 To 20
Console.Write("{0,8}", rnd.Next(1000, 10001))
If ctr Mod 5 = 0 Then Console.WriteLine()
Next
Console.WriteLine()
Console.WriteLine("20 random integers from 1 to 10:")
For ctr As Integer = 1 To 20
Console.Write("{0,6}", rnd.Next(1, 11))
If ctr Mod 5 = 0 Then Console.WriteLine()
Next
End Sub
End Module
' The example displays output similar to the following:
' 20 random integers from -100 to 100:
' 65 -95 -10 90 -35
' -83 -16 -15 -19 41
' -67 -93 40 12 62
' -80 -95 67 -81 -21
'
' 20 random integers from 1000 to 10000:
' 4857 9897 4405 6606 1277
' 9238 9113 5151 8710 1187
' 2728 9746 1719 3837 3736
' 8191 6819 4923 2416 3028
'
' 20 random integers from 1 to 10:
' 9 8 5 9 9
' 9 1 2 3 8
' 1 4 8 10 5
' 9 7 9 10 5
以下示例生成一个随机整数，该整数用作索引从数组中检索字符串值。 由于数组的最高索引小于其长度的 1，因此 属性的值 Array.Length 作为 maxValue 参数提供。
using namespace System;
void main()
{
Random^ rnd = gcnew Random();
array<String^>^ malePetNames = { "Rufus", "Bear", "Dakota", "Fido",
"Vanya", "Samuel", "Koani", "Volodya",
"Prince", "Yiska" };
array<String^>^ femalePetNames = { "Maggie", "Penny", "Saya", "Princess",
"Abby", "Laila", "Sadie", "Olivia",
"Starlight", "Talla" };
// Generate random indexes for pet names.
int mIndex = rnd->Next(0, malePetNames->Length);
int fIndex = rnd->Next(0, femalePetNames->Length);
// Display the result.
Console::WriteLine("Suggested pet name of the day: ");
Console::WriteLine(" For a male: {0}", malePetNames[mIndex]);
Console::WriteLine(" For a female: {0}", femalePetNames[fIndex]);
}
// The example displays the following output:
// Suggested pet name of the day:
// For a male: Koani
// For a female: Maggie
Random rnd = new();
string[] malePetNames = [ "Rufus", "Bear", "Dakota", "Fido",
"Vanya", "Samuel", "Koani", "Volodya",
"Prince", "Yiska" ];
string[] femalePetNames = [ "Maggie", "Penny", "Saya", "Princess",
"Abby", "Laila", "Sadie", "Olivia",
"Starlight", "Talla" ];
// Generate random indexes for pet names.
int mIndex = rnd.Next(0, malePetNames.Length);
int fIndex = rnd.Next(0, femalePetNames.Length);
// Display the result.
Console.WriteLine("Suggested pet name of the day: ");
Console.WriteLine($" For a male: {malePetNames[mIndex]}");
Console.WriteLine($" For a female: {femalePetNames[fIndex]}");
// The example displays the following output:
// Suggested pet name of the day:
// For a male: Koani
// For a female: Maggie
let rnd = Random()
let malePetNames =
[| "Rufus"; "Bear"; "Dakota"; "Fido";
"Vanya"; "Samuel"; "Koani"; "Volodya";
"Prince"; "Yiska" |]
let femalePetNames =
[| "Maggie"; "Penny"; "Saya"; "Princess";
"Abby"; "Laila"; "Sadie"; "Olivia";
"Starlight"; "Talla" |]
// Generate random indexes for pet names.
let mIndex = rnd.Next(0, malePetNames.Length)
let fIndex = rnd.Next(0, femalePetNames.Length)
// Display the result.
printfn "Suggested pet name of the day: "
printfn " For a male: %s" malePetNames.[mIndex]
printfn " For a female: %s" femalePetNames.[fIndex]
// The example displays output similar to the following:
// Suggested pet name of the day:
// For a male: Koani
// For a female: Maggie
Module Example
Public Sub Main()
Dim rnd As New Random()
Dim malePetNames() As String = { "Rufus", "Bear", "Dakota", "Fido",
"Vanya", "Samuel", "Koani", "Volodya",
"Prince", "Yiska" }
Dim femalePetNames() As String = { "Maggie", "Penny", "Saya", "Princess",
"Abby", "Laila", "Sadie", "Olivia",
"Starlight", "Talla" }
' Generate random indexes for pet names.
Dim mIndex As Integer = rnd.Next(0, malePetNames.Length)
Dim fIndex As Integer = rnd.Next(0, femalePetNames.Length)
' Display the result.
Console.WriteLine("Suggested pet name of the day: ")
Console.WriteLine(" For a male: {0}", malePetNames(mIndex))
Console.WriteLine(" For a female: {0}", femalePetNames(fIndex))
End Sub
End Module
' The example displays output like the following:
' Suggested pet name of the day:
' For a male: Koani
' For a female: Maggie
注解
重 Next(Int32, Int32) 载返回范围从 minValue 到 maxValue - 1 的随机整数。 但是，如果 maxValue 等于 minValue，则 方法返回 minValue。
与仅返回非负值的方法的其他重载 Next 不同，此方法可以返回负随机整数。
继承者说明
从 .NET Framework 版本 2.0 开始，如果从 Random 派生类并重写Sample()方法，则如果 和 maxValue 参数之间的差异大于 Int32.MaxValue，则不会在调用方法重载的Next(Int32, Int32)基类实现时minValue使用该方法的Sample()派生类实现提供的分布。 而是使用基 Random 类返回的统一分布。 此行为可提高 类的整体性能 Random 。 若要修改此行为以调用 Sample() 派生类中的 方法，还必须重写 Next(Int32, Int32) 方法重载。
