Namespaces
Variants
Views
Actions

std::in_range

From cppreference.com
< cpp‎ | utility
 
 
Utilities library
Language support
Type support (basic types, RTTI)
Library feature-test macros (C++20)
Dynamic memory management
Program utilities
Coroutine support (C++20)
Variadic functions
Debugging support
(C++26)
Three-way comparison
(C++20)
(C++20)(C++20)(C++20)
(C++20)(C++20)(C++20)
General utilities
Date and time
Function objects
Formatting library (C++20)
(C++11)
Relational operators (deprecated in C++20)
Integer comparison functions
(C++20)(C++20)(C++20)   
in_range
(C++20)
Swap and type operations
(C++14)
(C++11)
(C++11)
(C++11)
(C++17)
Common vocabulary types
(C++11)
(C++17)
(C++17)
(C++17)
(C++11)
(C++17)
(C++23)
Elementary string conversions
(C++17)
(C++17)

 
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.

Contents

[edit] Parameters

t - value to test

[edit] Return value

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

[edit] 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());
}

[edit] 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

[edit] 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';
}

Output:

false
true

[edit] See also

returns the smaller of the given values
(niebloid)[edit]
returns the greater of the given values
(niebloid)[edit]
clamps a value between a pair of boundary values
(niebloid)[edit]
(C++20)
linear interpolation function
(function) [edit]