Byte Array to Float Conversion C#

Question

I have tried the below C# code to convert from hex literal to floating point and get the correct result. I wish to input a byte array instead and have that converted to floating point but can't seem to get it right result.

0x4229ec00 is the current format. I need it in byte array format something like...

new byte[]{ 0x01, 0x04, 0x01, 0x60, 0x00, 0x02, 0x70, 0x29}; //current output 42.48

The code looks like:

byte[] bytes = BitConverter.GetBytes(0x4229ec00);
float myFloat = floatConversion(bytes);

public float floatConversion(byte[] bytes)
{
    float myFloat = BitConverter.ToSingle(bytes, 0);
    return myFloat;
}

Any help would be greatly appreciated. Thank you!

@JamesBarrass: He's converting 4 bytes, not 8: #42, #29, #ec and #00. — Roy Dictus
– Roy Dictus, Commented Jan 30, 2014 at 10:47
@RoyDictus: "something like... 0x01, 0x04, 0x01, 0x60, 0x00, 0x02, 0x70, 0x29 — James
– James, Commented Jan 30, 2014 at 10:50
@Maria88: the size of float is indeed 4 bytes, not 8, so if you are converting that 8-byte array to a floating point, it won't be a float but a double. — Roy Dictus
– Roy Dictus, Commented Jan 30, 2014 at 10:50
Please describe the problem clearly. You want to convert an array of 4N bytes into N floats. Is that it? What part are you stuck on? — David Heffernan
– David Heffernan, Commented Jan 30, 2014 at 10:55
What we are struggling with is what you want to do with 8 bytes. Convert them into two floats, or one double. And some clarity on the byte ordering would help. Why are your bytes in that order? Do they arrive down the wire? — David Heffernan
– David Heffernan, Commented Jan 30, 2014 at 11:12

Rajnikant · Accepted Answer · 2014-01-30 11:13:08Z

7

You can amend your float conversion function as below

    public float floatConversion(byte[] bytes)
    {
        if (BitConverter.IsLittleEndian)
        {
            Array.Reverse(bytes); // Convert big endian to little endian
        }
        float myFloat = BitConverter.ToSingle(bytes, 0);
        return myFloat;
    }

answered Jan 30, 2014 at 11:13

Rajnikant

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Dmitrii Bychenko · Accepted Answer · 2014-01-30 11:15:56Z

2

float (Single) is a 4 Byte value;

Your test value 0x4229ec00 contains 4 bytes, they are: 0x42, 0x29, 0xEC, 0x00

x86 CPUs use reversed order of bytes (Little Endian), so the right byte array is

0x00, 0xEC, 0x29, 0x42

The Code

// Original array
Byte[] data = new Byte[] {0x42, 0x29, 0xEC, 0x00};
// 42.48047
// If CPU uses Little Endian, we should reverse the data 
float result = BitConverter.ToSingle(BitConverter.IsLittleEndian? data.Reverse().ToArray() : data, 0);

edited Jan 30, 2014 at 11:15

answered Jan 30, 2014 at 10:51

Dmitrii Bychenko

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4 Comments

David Heffernan Over a year ago

@Maria88 We are all looking to help. We just need some more info. The question you asked is not clear.

kelevra88 Over a year ago

Very Sorry if i offended you,was just looking for some help,ill be more clear next time ,Very Sorry,Can anyone help with the reversal of the bytes in the byte array ,is there a simple one line conversion?

Dmitrii Bychenko Over a year ago

@Maria88: Yes, you can do it in one line, see my edit

kelevra88 Over a year ago

Thats been a great contribution thank you very much,i continue to have the best respect for this website and will try to contribute also when i can ,its because of people like you that software engineering has come so far,thank you

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