std:: in_range

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

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 .

Example

#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';
}

false
true

See also