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 lower and upper?

Of course, using a bunch of if statements can do this, but that’s boring! What about more compact and elegant/fun solutions?

My own quick attempt (C/C++):

float clip( float n, float lower, float upper )
{
    n = ( n > lower ) * n + !( n > lower ) * lower;
    return ( n < upper ) * n + !( n < upper ) * upper;
}

I’m sure there are other, better ways to do this, that’s why I’m putting this out there..!

Answer 1

What about boring, old, readable, and shortest yet:

float clip(float n, float lower, float upper) {
  return std::max(lower, std::min(n, upper));
}

?

This expression could also be ‘genericized’ like so:

template <typename T>
T clip(const T& n, const T& lower, const T& upper) {
  return std::max(lower, std::min(n, upper));
}

Update

Billy ONeal added:

Note that on windows you might have to define NOMINMAX because they define min and max macros which conflict