I need to convert float to int (single precision, 32 bits) like:
'float: 2 (hex: 40000000) to int: 1073741824'. Any idea how to implement that?
I was looking for it in msdn help but with no result.
- [link] babbage.cs.qc.edu/IEEE-754/Decimal.htmlsantBart– santBart2011-08-24 10:08:39 +00:00Commented Aug 24, 2011 at 10:08
- In effect, you want a bit-wise copy? Like C++'s reinterpret_cast?Skizz– Skizz2011-08-24 10:09:04 +00:00Commented Aug 24, 2011 at 10:09
- Have a look here stackoverflow.com/questions/2578348/…castleofbones– castleofbones2011-08-24 10:15:07 +00:00Commented Aug 24, 2011 at 10:15
- I'm not sure convert is the right verb.Jodrell– Jodrell2011-08-24 10:21:58 +00:00Commented Aug 24, 2011 at 10:21
- @castleofbones: that link is to conversions that preserve the represented number. The OP is after a conversion that preserves the binary representation.Paul Ruane– Paul Ruane2011-08-24 10:51:11 +00:00Commented Aug 24, 2011 at 10:51
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4 Answers
float f = ...; int i = BitConverter.ToInt32(BitConverter.GetBytes(f), 0); answered Aug 24, 2011 at 10:32
David Heffernan
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BitConverter.DoubleToInt64Bits, as per the accepted answer of this question.
If the above solution is no good for you (due to it acting upon double/Double rather than float/Single) then see David Heffernan's answer.
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David Heffernan
question is about 4 byte float and int
David THANKS, that was a short answer of my long search of analogue for Java method: Float.floatToIntBits. Here is the entire code:
static void Main() { float tempVar = -27.25f; int intBits = BitConverter.ToInt32(BitConverter.GetBytes(tempVar), 0); string input = Convert.ToString(intBits, 2); input = input.PadLeft(32, '0'); string sign = input.Substring(0, 1); string exponent = input.Substring(1, 8); string mantissa = input.Substring(9, 23); Console.WriteLine(); Console.WriteLine("Sign = {0}", sign); Console.WriteLine("Exponent = {0}", exponent); Console.WriteLine("Mantissa = {0}", mantissa); } 
Comments
If your aiming for versions less than .Net 4 where BitConverter isn't available, or you want to convert floats to 32 bit ints, use a memory stream:
using System; using System.IO; namespace Stream { class Program { static void Main (string [] args) { float f = 1; int i; MemoryStream s = new MemoryStream (); BinaryWriter w = new BinaryWriter (s); w.Write (f); s.Position = 0; BinaryReader r = new BinaryReader (s); i = r.ReadInt32 (); s.Close (); Console.WriteLine ("Float " + f + " = int " + i); } } } It is a bit long winded though.
