How to get the IEEE 754 binary representation of a float in C#

Question

I have some single and double precision floats that I want to write to and read from a byte[]. Is there anything in .Net I can use to convert them to and from their 32 and 64 bit IEEE 754 representations?

Answer 1

.NET Single and Double are already in IEEE-754 format. You can use BitConverter.ToSingle() and ToDouble() to convert byte[] to floating point, GetBytes() to go the other way around.

Answer 2

Update for current .NET/C# using spans:

static void Main() {     Span<byte> data = stackalloc byte[20];     GetBytes(0, data, 0);     GetBytes(123.45F, data, 4);     GetBytes(123.45D, data, 8); }  static unsafe void GetBytes(float value, Span<byte> buffer, int offset)     => MemoryMarshal.Cast<byte, float>(buffer.Slice(offset))[0] = value; static unsafe void GetBytes(double value, Span<byte> buffer, int offset)     => MemoryMarshal.Cast<byte, double>(buffer.Slice(offset))[0] = value; 

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If you don't want to allocate new arrays all the time (which is what GetBytes does), you can use unsafe code to write to a buffer directly:

static void Main() {     byte[] data = new byte[20];     GetBytes(0, data, 0);     GetBytes(123.45F, data, 4);     GetBytes(123.45D, data, 8); }  static unsafe void GetBytes(float value, byte[] buffer, int offset) {     fixed (byte* ptr = &buffer[offset])     {         float* typed = (float*)ptr;         *typed = value;     } } static unsafe void GetBytes(double value, byte[] buffer, int offset) {     fixed (byte* ptr = &buffer[offset])     {         double* typed = (double*)ptr;         *typed = value;     } }