float to Binary (Ex. 15.375 = 1111.011b)

This is a discussion on float to Binary (Ex. 15.375 = 1111.011b) within the A Brief History of Cprogramming.com forums, part of the Community Boards category; I was wondering if someone could shed some light on this. Some calculators output their binary numbers this way, Ex. ...

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    Registered User Noose's Avatar
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    float to Binary (Ex. 15.375 = 1111.011b)

    I was wondering if someone could shed some light on this. Some calculators output their binary numbers this way, Ex. 15 = 1111.b, 15.375 = 1111.011b. How would you create a binary string "1111.011b" from a float. Not the actual writing of the string and not so much the integer part but the fraction part. Im looking for the process, not a function call.

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    Search the Web for "binary" and "floating point".
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    Quote Originally Posted by Noose View Post
    I was wondering if someone could shed some light on this. Some calculators output their binary numbers this way, Ex. 15 = 1111.b, 15.375 = 1111.011b. How would you create a binary string "1111.011b" from a float. Not the actual writing of the string and not so much the integer part but the fraction part. Im looking for the process, not a function call.
    Essentially, the opposite of the code posted - and no, don't expect me to write that one too!

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    1. Start with a "number" set to .5
    2. If the fractional part of the value we are converting to binary is greater than (or equal to) this "number", output a 1 and subtract the "number" from the fraction. If not, just output a 0.
    3. Multiply the above "number" by half (0.5 becomes .25, .25 becomes .125)
    4. Go back to step 2 until there is no more fraction or you're at the desired accuracy
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    l'Anziano DavidP's Avatar
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    Place Values in the Decimal System:

    100 10 1 [Decimal Point] 1/10 1/100 1/1000

    Place Values in the Binary System:

    4 2 1 [Decimal Point] 1/2 1/4 1/8
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