Convert to absolute value in Objective-C
Objective CObjective C Problem Overview
How do I convert a negative number to an absolute value in Objective-C?
i.e.
-10
becomes
10?
Objective C Solutions
Solution 1 - Objective C
Depending on the type of your variable, one of abs(int), labs(long), llabs(long long), imaxabs(intmax_t), fabsf(float), fabs(double), or fabsl(long double).
Those functions are all part of the C standard library, and so are present both in Objective-C and plain C (and are generally available in C++ programs too.)
(Alas, there is no habs(short) function. Or scabs(signed char) for that matter...)
Apple's and GNU's Objective-C headers also include an ABS() macro which is type-agnostic. I don't recommend using ABS() however as it is not guaranteed to be side-effect-safe. For instance, ABS(a++) will have an undefined result.
If you're using C++ or Objective-C++, you can bring in the <cmath> header and use std::abs(), which is templated for all the standard integer and floating-point types.
Solution 2 - Objective C
You can use this function to get the absolute value:
+(NSNumber *)absoluteValue:(NSNumber *)input {
return [NSNumber numberWithDouble:fabs([input doubleValue])];
}
Solution 3 - Objective C
If you are curious as to what they are doing in the abs() function:
char abs(char i) {
return -(i & 128) ^ i;
}