std::in_range

 

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Defined in header <utility>
template< class R, class T > constexpr bool in_range( T t ) noexcept;		(since C++20)

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