# Objective-C – Get number of decimals of a double variable

Is there a nice way to get the number of decimals of a double variable in Objective-C?
I am struggling for a while to find a way but with no success.

For example 231.44232000 should return 5.

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### 2 Solutions Collect From Internet About “Objective-C – Get number of decimals of a double variable”

You could, in a loop, multiply by 10 until the fractional part (returned by modf()) is really close to zero. The number of iterations’ll be the answer you’re after. Something like:

``````int countDigits(double num) {
int rv = 0;
const double insignificantDigit = 8;
double intpart, fracpart;
fracpart = modf(num, &intpart);
while ((fabs(fracpart) > 0.000000001f) && (rv < insignificantDigit)) {
num *= 10;
rv++;
fracpart = modf(num, &intpart);
}

return rv;
}
``````

Is there a nice way to get the number of decimals of a double variable in Objective-C?

No. For starters, a double stores a number in binary, so there may not even be an exact binary representation that corresponds to your decimal number. There’s also no consideration for the number of significant decimal digits — if that’s important, you’ll need to track it separately.

You might want to look into using NSDecimalNumber if you need to store an exact representation of a decimal number. You could create your own subclass and add the ability to store and track significant digits.