27 Algorithms library [algorithms]

27.8 Sorting and related operations [alg.sorting]

27.8.10 Bounded value [alg.clamp]

template<class T>
  constexpr const T& clamp(const T& v, const T& lo, const T& hi);
template<class T, class Compare>
  constexpr const T& clamp(const T& v, const T& lo, const T& hi, Compare comp);
template<class T, class Proj = identity,
         indirect_strict_weak_order<projected<const T*, Proj>> Comp = ranges::less>
  constexpr const T&
    ranges::clamp(const T& v, const T& lo, const T& hi, Comp comp = {}, Proj proj = {});

Let comp be less{} for the overloads with no parameter comp, and let proj be identity{} for the overloads with no parameter proj.

Preconditions: bool(invoke(comp, invoke(proj, hi), invoke(proj, lo))) is false.

For the first form, type T meets the Cpp17LessThanComparable requirements (Table 29).

Returns: lo if bool(invoke(comp, invoke(proj, v), invoke(proj, lo))) is true, hi if bool(invoke(comp, invoke(proj, hi), invoke(proj, v))) is true, otherwise v.

[Note 1:

If NaN is avoided, T can be a floating-point type.

— end note]

Complexity: At most two comparisons and three applications of the projection.