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BitConverter::ToDouble Method

Returns a double-precision floating point number converted from eight bytes at a specified position in a byte array.

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

public:
static double ToDouble(
	array<unsigned char>^ value, 
	int startIndex
)

Parameters

value
Type: array<System::Byte>
An array of bytes.
startIndex
Type: System::Int32
The starting position within value.

Return Value

Type: System::Double
A double precision floating point number formed by eight bytes beginning at startIndex.

ExceptionCondition
ArgumentException

startIndex is greater than or equal to the length of value minus 7, and is less than or equal to the length of value minus 1.

ArgumentNullException

value is nullptr.

ArgumentOutOfRangeException

startIndex is less than zero or greater than the length of value minus 1.

The following code example converts elements of Byte arrays to Double values with the ToDouble method.


// Example of the BitConverter::ToDouble method.
using namespace System;

// Convert eight byte array elements to a double and display it.
void BAToDouble( array<unsigned char>^bytes, int index )
{
   double value = BitConverter::ToDouble( bytes, index );
   Console::WriteLine( "{0,5}{1,27}{2,27:E16}", index, BitConverter::ToString( bytes, index, 8 ), value );
}


// Display a byte array, using multiple lines if necessary.
void WriteMultiLineByteArray( array<unsigned char>^bytes )
{
   const int rowSize = 20;
   int iter;
   Console::WriteLine( "initial unsigned char array" );
   Console::WriteLine( "---------------------------" );
   for ( iter = 0; iter < bytes->Length - rowSize; iter += rowSize )
   {
      Console::Write( BitConverter::ToString( bytes, iter, rowSize ) );
      Console::WriteLine( "-" );

   }
   Console::WriteLine( BitConverter::ToString( bytes, iter ) );
   Console::WriteLine();
}

int main()
{
   array<unsigned char>^byteArray = {0,0,0,0,0,0,0,0,240,63,0,0,0,0,0,224,111,64,0,0,224,255,255,255,239,65,0,0,0,0,0,0,112,63,0,0,0,0,0,0,240,61,223,136,30,28,254,116,170,1,250,89,140,66,202,192,243,63,251,89,140,66,202,192,243,63,252,89,140,66,202,192,243,63,82,211,187,188,232,126,61,126,255,255,255,255,255,255,239,255,255,255,255,255,255,239,127,1,0,0,0,0,0,0,0,248,255,0,0,0,0,0,0,240,255,0,0,0,0,0,0,240,127};
   Console::WriteLine( "This example of the BitConverter::ToDouble( unsigned "
   "char[ ], int ) \nmethod generates the following output. It "
   "converts elements of a \nbyte array to double values.\n" );
   WriteMultiLineByteArray( byteArray );
   Console::WriteLine( "{0,5}{1,27}{2,27:E16}", "index", "array elements", "double" );
   Console::WriteLine( "{0,5}{1,27}{2,27:E16}", "-----", "--------------", "------" );

   // Convert byte array elements to double values.
   BAToDouble( byteArray, 0 );
   BAToDouble( byteArray, 2 );
   BAToDouble( byteArray, 10 );
   BAToDouble( byteArray, 18 );
   BAToDouble( byteArray, 26 );
   BAToDouble( byteArray, 34 );
   BAToDouble( byteArray, 42 );
   BAToDouble( byteArray, 50 );
   BAToDouble( byteArray, 58 );
   BAToDouble( byteArray, 66 );
   BAToDouble( byteArray, 74 );
   BAToDouble( byteArray, 82 );
   BAToDouble( byteArray, 89 );
   BAToDouble( byteArray, 97 );
   BAToDouble( byteArray, 99 );
   BAToDouble( byteArray, 107 );
   BAToDouble( byteArray, 115 );
}

/*
This example of the BitConverter.ToDouble( byte( ), int )
method generates the following output. It converts elements
of a byte array to double values.

initial byte array
------------------
00-00-00-00-00-00-00-00-F0-3F-00-00-00-00-00-E0-6F-40-00-00-
E0-FF-FF-FF-EF-41-00-00-00-00-00-00-70-3F-00-00-00-00-00-00-
F0-3D-DF-88-1E-1C-FE-74-AA-01-FA-59-8C-42-CA-C0-F3-3F-FB-59-
8C-42-CA-C0-F3-3F-FC-59-8C-42-CA-C0-F3-3F-52-D3-BB-BC-E8-7E-
3D-7E-FF-FF-FF-FF-FF-FF-EF-FF-FF-FF-FF-FF-FF-EF-7F-01-00-00-
00-00-00-00-00-F8-FF-00-00-00-00-00-00-F0-FF-00-00-00-00-00-
00-F0-7F

index             array elements                     double
-----             --------------                     ------
    0    00-00-00-00-00-00-00-00    0.0000000000000000E+000
    2    00-00-00-00-00-00-F0-3F    1.0000000000000000E+000
   10    00-00-00-00-00-E0-6F-40    2.5500000000000000E+002
   18    00-00-E0-FF-FF-FF-EF-41    4.2949672950000000E+009
   26    00-00-00-00-00-00-70-3F    3.9062500000000000E-003
   34    00-00-00-00-00-00-F0-3D    2.3283064365386963E-010
   42    DF-88-1E-1C-FE-74-AA-01    1.2345678901234500E-300
   50    FA-59-8C-42-CA-C0-F3-3F    1.2345678901234565E+000
   58    FB-59-8C-42-CA-C0-F3-3F    1.2345678901234567E+000
   66    FC-59-8C-42-CA-C0-F3-3F    1.2345678901234569E+000
   74    52-D3-BB-BC-E8-7E-3D-7E    1.2345678901234569E+300
   82    FF-FF-FF-FF-FF-FF-EF-FF   -1.7976931348623157E+308
   89    FF-FF-FF-FF-FF-FF-EF-7F    1.7976931348623157E+308
   97    01-00-00-00-00-00-00-00    4.9406564584124654E-324
   99    00-00-00-00-00-00-F8-FF                        NaN
  107    00-00-00-00-00-00-F0-FF                  -Infinity
  115    00-00-00-00-00-00-F0-7F                   Infinity
*/


.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.
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