Most efficient/elegant way to clip a number?

Question

Given a real (n), a maximum value this real can be (upper), and a minimum value this real can be (lower), how can we most efficiently clip n, such that it remains between lo

Answer 1

The following header file should work for C and C++. Note that it undefines min and max if the macros are already defined:

#pragma once

#ifdef min
#undef min
#endif

#ifdef max
#undef max
#endif

#ifdef __cplusplus
#include 

template 
T clip(T in, T low, T high)
{
    return std::min(std::max(in, low), high);
}
#else /* !__cplusplus */
#define min(a, b) (((a) < (b)) ? (a) : (b))
#define max(a, b) (((a) < (b)) ? (b) : (a))
#define clip(a, b, c) min(max((a), (b)), (c))
#endif /* __cplusplus */