Is There a Standard Sign Function in C/C for Determining the Sign of Numerical Values?

Determining the Sign of Numerical Values in C/C

In programming, determining the sign of numerical values ( 1 for positive, -1 for negative) is a common operation. While it's possible to implement custom sign calculation functions, one may wonder if there's a standardized solution.

Standard Sign Function in C/C

No, there is no standard sign function provided by the C or C standard libraries specifically for numerical types.

Alternative Options for Float Sign Calculation

Although there's no dedicated sign function, there are alternative methods to calculate the sign of floating-point numbers. One popular approach uses the copysign function, which returns a new value with the absolute value of the provided number and the sign of another specified number. For instance, you can use it as follows:

#include <math.h>
int sign(float val) {
  return copysign(1.0f, val);
}

Type-Safe C Sign Function

A more type-safe and portable solution is to define a generic sign function using templates:

template <typename T>
int sgn(T val) {
  return (T(0) < val) - (val < T(0));
}

This function works for any type that can be compared to zero and supports both signed and unsigned types.

Benefits and Caveats

The sgn function is efficient, standards-compliant, and accurate. However, it's a template, which may introduce compilation time overheads in certain scenarios.

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