How to calculate number of digits after floating point in iOS? - ios

Question

How can I calculate the number of digits after the floating point in iOS?
For example:
3.105 should return 3
3.0 should return 0
2.2 should return 1
Update:
Also we need to add the following example. As I want to know number of digits in the fraction part.
1e-1 should return 1

Answer 1

Try this way:
NSString *enteredValue=#"99.1234";
NSArray *array=[enteredValue componentsSeparatedByString:#"."];
NSLog(#"->Count : %ld",[array[1] length]);

Answer 2

What I used is the following:
NSString *priorityString = [[NSNumber numberWithFloat:self.priority] stringValue];
NSRange range = [priorityString rangeOfString:#"."];
int digits;
if (range.location != NSNotFound) {
priorityString = [priorityString substringFromIndex:range.location + 1];
digits = [priorityString length];
} else {
range = [priorityString rangeOfString:#"e-"];
if (range.location != NSNotFound) {
priorityString = [priorityString substringFromIndex:range.location + 2];
digits = [priorityString intValue];
} else {
digits = 0;
}
}

Answer 3

Maybe there is a more elegant way to do this, but when converting from a 32 bit architecture app to a 64 bit architecture, many of the other ways I found lost precision and messed things up. So here's how I do it:
bool didHitDot = false;
int numDecimals = 0;
NSString *doubleAsString = [doubleNumber stringValue];
for (NSInteger charIdx=0; charIdx < doubleAsString.length; charIdx++){
if ([doubleAsString characterAtIndex:charIdx] == '.'){
didHitDot = true;
}
if (didHitDot){
numDecimals++;
}
}
//numDecimals now has the right value