How to convert decimal (or float) to binary? C#

Question

I have this given number, for example, 10.5, and I want to convert it into its binary representation. The result should be 1010.1. How to achieve that in C#?

Why would a binary value have a decimal point in it? If you _really_ want to keep the ending decimal point, just do two conversions, once for the stuff to the left, and once for the right, see the link below. — gunr2171, May 11 '21 at 04:05
Does this answer your question? [Convert integer to binary in C#](https://stackoverflow.com/questions/2954962/convert-integer-to-binary-in-c-sharp) — gunr2171, May 11 '21 at 04:06
I don't understand the downvotes. That's a perfectly reasonable question - "1010.1" *is* the representation of 10.5 in base 2: 1*2^3 + 1*2^0 + 1*2^-1 — Klaus Gütter, May 11 '21 at 05:07

score 1 · Answer 1 · answered May 11 '21 at 05:20

To convert the part before the decimal point, you can just use the built-in Convert.ToString(integerPart, 2)

I don't believe there is such a built-in function for the fractional part, but you can do it like you learned in school for the decimal case:

// x must be < 1
string ConvertFractionalPart(double x, int maxDigits)
{
    var sb = new StringBuilder();
    while (x > 0 && sb.Length < maxDigits)
    {
        if (x >= 0.5)
        {
            sb.Append("1");
            x -= 0.5;
        }
        else
        {
            sb.Append("0");
        }
        x = 2*x;
    }
    return sb.ToString();
}

How to convert decimal (or float) to binary? C#

1 Answers1