This documentation is archived and is not being maintained.

Random.Next Method (Int32)

Returns a nonnegative random number less than the specified maximum.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

public virtual int Next(
	int maxValue
)

Parameters

maxValue
Type: System.Int32
The exclusive upper bound of the random number to be generated. maxValue must be greater than or equal to zero.

Return Value

Type: System.Int32
A 32-bit signed integer greater than or equal to zero, and less than maxValue; that is, the range of return values ordinarily includes zero but not maxValue. However, if maxValue equals zero, maxValue is returned.

ExceptionCondition
ArgumentOutOfRangeException

maxValue is less than zero.

The following example generates random integers with various overloads of the Next method.


// Example of the Random.Next( ) methods.
using System;

public class RandomNextDemo  
{
    // Generate random numbers with no bounds specified.
    static void NoBoundsRandoms( int seed )
    {
        Console.WriteLine( 
            "\nRandom object, seed = {0}, no bounds:", seed );
        Random randObj = new 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.
    static void UpperBoundRandoms( int seed, int upper )
    {
        Console.WriteLine( 
            "\nRandom object, seed = {0}, upper bound = {1}:", 
            seed, upper );
        Random randObj = new 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.
    static void BothBoundsRandoms( int seed, int lower, int upper )
    {
        Console.WriteLine( 
            "\nRandom object, seed = {0}, lower = {1}, " +
            "upper = {2}:", seed, lower, upper );
        Random randObj = new 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( );
    }

    static void 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
*/


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Show: