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)