Check if float value is integer

Question

In Objective C, how can I check if value is integer number like 2.000 , 3.000, 8.000 stored as a float, and not a fraction like 2.456, 3.578

"a perfect number is a positive integer that is equal to the sum of its proper positive divisors" All you want to know is if it has decimals or not, am I correct? — David Rönnqvist
– David Rönnqvist, Commented Nov 16, 2013 at 13:11
You need to define whether you mean an exact integer (which is possible in IEEE float but not some other float formats) or simply something that appears to be an integer to a given level of precision. — Hot Licks
– Hot Licks, Commented Nov 16, 2013 at 13:19
@HotLicks I have float number which increases from 0.000 to 12.000. I want to fire action when number is integer like 1.000,2.000 etc. — sourabhkumbhar
– sourabhkumbhar, Commented Nov 16, 2013 at 13:35
@SourabhKumbhar Adding random fractions which are not exactly representable, such as 0.012, 0.157, 0.587, is very unlikely to result in an exact integer. You should probably allow a range around each integer. — Patricia Shanahan
– Patricia Shanahan, Commented Nov 16, 2013 at 14:53

godel9 · Accepted Answer · 2013-11-16 13:12:18Z

24

I think you're asking how to find out if a number stored as a float is an integer. There are a number of techniques. Here's one:

if(fVal == floorf(fVal))
    ... // do something

answered Nov 16, 2013 at 13:12

godel9

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1 Comment

Supertecnoboff Over a year ago

Thank you so much for this!! I have been trying for the last two days to achieve this basic functionality and failed (lol).... You are a life saver!!

zaph · Accepted Answer · 2013-11-16 14:35:58Z

14

Use the floating point remainder function:

if (fmod(fVal, 1.0) == 0.0)
   // is integer

or

BOOL isInteger = !fmod(fVal, 1.0);

edited Nov 16, 2013 at 14:35

answered Nov 16, 2013 at 13:22

zaph

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Comments

3CC · Accepted Answer · 2019-11-15 09:12:19Z

4

I believe it's the simplest way to check it:

if( fnum == (int)fnum ) {
    //fnum has integer value without decimals
}

edited Nov 15, 2019 at 9:12

answered Jan 27, 2015 at 15:15

3CC

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paulrehkugler · Accepted Answer · 2013-11-16 14:00:42Z

2

I personally like

 #define F_ISWHOLENUM(_float) (!fmod(_float, 1.0f))

answered Nov 16, 2013 at 14:00

paulrehkugler

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Comments

hariszaman · Accepted Answer · 2016-11-09 12:24:14Z

0

float number = myNum.floatValue;
 CFNumberType numberType = CFNumberGetType((CFNumberRef)myNum);
if(number == floorf(number) && (number == 1 || number == 0))
{
    // It is a bool (Exceptions 1.000, 0.00000)
}
else
{
    // It is some other number use numberTyoe here except kCFNumberCharType
    if (numberType == kCFNumberSInt32Type) {

    }
}

answered Nov 9, 2016 at 12:24

hariszaman

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