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Random::NextDouble Method
Visual Studio 2010
Returns a random number between 0.0 and 1.0.
Assembly: mscorlib (in mscorlib.dll)
Return Value
Type: System::DoubleA double-precision floating point number greater than or equal to 0.0, and less than 1.0.
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; using namespace System::Threading; // 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. Thread::Sleep( 1 ); 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 */
The following example calls the NextDouble method to generate 100 random numbers and displays their frequency distribution.
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.
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