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std::chrono::day::ok

constexpr bool ok() const noexcept;
 (since C++20)

Checks if the day value stored in *this is in the valid range, i.e., [1, 31].

Return value

true if the day value stored in *this is in the range [1, 31]. Otherwise false.

Example 

#include <iostream>
#include <chrono>
 
int main()
{
    std::chrono::day d1{15};
    std::cout << static_cast<unsigned>(d1);
    if (d1.ok()) {
        std::cout << " is a valid day.\n";
    } else {
        std::cout << " is an invalid day!\n";
    }
 
    std::chrono::day d2{35};
    std::cout << static_cast<unsigned>(d2)
              << (d2.ok() ? " is a valid day.\n"
                          : " is an invalid day!\n");
}

Output:

15 is a valid day.
35 is an invalid day!

See also

retrieves the stored day value
(public member function)

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