std::in_range(3)

NAME
std::in_range - std::in_range

Synopsis
   Defined in header <utility>
   template< class R, class T > (since C++20)
   constexpr bool in_range( T t ) noexcept;
   Returns true if the value of t is in the range of values that can be represented in
   R, that is, if t can be converted to R in a value-preserving manner.
   It is a compile-time error if either T or U is a non-integer type, a character type,
   or bool.

Parameters
   t - value to test

Return value
   true if the value of t is representable in R, false otherwise.

Possible implementation
   template<class R, class T>
   constexpr bool in_range(T t) noexcept
   {
       return std::cmp_greater_equal(t, std::numeric_limits<R>::min()) &&
           std::cmp_less_equal(t, std::numeric_limits<R>::max());
   }

Notes
   This function cannot be used with enums (including std::byte), char, char8_t,
   char16_t, char32_t, wchar_t and bool.
             Feature-test macro Value Std Feature
   __cpp_lib_integer_comparison_functions 202002L (C++20) Integer comparison functions

Example
// Run this code
 #include <iostream>
 #include <utility>
 int main()
 {
     std::cout << std::boolalpha;
     std::cout << std::in_range<std::size_t>(-1) << '\n';
     std::cout << std::in_range<std::size_t>(42) << '\n';
 }

Output:
 false
 true

See also
   ranges::min returns the smaller of the given values
   (C++20) (niebloid)
   ranges::max returns the greater of the given values
   (C++20) (niebloid)
   ranges::clamp clamps a value between a pair of boundary values
   (C++20) (niebloid)
   lerp linear interpolation function
   (C++20) (function)