Why use abs() or fabs() instead of conditional negation?

Question

In C/C++, why should one use abs() or fabs() to find the absolute value of a variable without using the following code?

int absoluteVal         


        

Answer 1

The intent behind abs() is "(unconditionally) set the sign of this number to positive". Even if that had to be implemented as a conditional based on the current state of the number, it's probably more useful to be able to think of it as a simple "do this", rather than a more complex "if… this… that".