std::chrono::weekday::ok(3)

💖 NAME 💖

bestie, welcome to the std::chrono::weekday::ok(3) page in the C++ Standard Libary manual. The star of the show is std::chrono::weekday::ok — and yes, the NAME line literally says std::chrono::weekday::ok - std::chrono::weekday::ok. iconic behavior, no notes. 💅

✨ Synopsis ✨

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

okay so this lil const member checks if the weekday value stored in *this is in the valid range, i.e., [0, 6]. that's the whole vibe check. 🦋

🎀 Return value 🎀

• true — if the weekday value stored in *this is in the range [0, 6].
• false — otherwise.

literally that's it. lowkey elegant. ✨

🦋 Example 🦋

run this code, bestie — it's giving custom numpunct locale energy, and the truename/falsename are doing the absolute most 🫶

// Run this code

#include <chrono>
#include <iomanip>
#include <iostream>
#include <locale>
#include <string>

struct weekday_ok : std::numpunct<char>
{
    std::string do_truename()  const override { return " (is valid weekday)"; }
    std::string do_falsename() const override { return " (is not valid weekday)"; }
};

int main()
{
    std::cout.imbue(std::locale(std::cout.getloc(), new weekday_ok));
    std::cout << std::boolalpha;

    for (const unsigned u : {0 /* Sun */, 1 /* Mon */, 6, 7 /* Sun */, 8, 9})
    {
        const std::chrono::weekday wd{u};
        std::cout << "u: " << u << "; wd: " << wd.c_encoding() << wd.ok() << '\n';
    }
}

🌈 Output 🌈

u: 0; wd: 0 (is valid weekday)
u: 1; wd: 1 (is valid weekday)
u: 6; wd: 6 (is valid weekday)
u: 7; wd: 0 (is valid weekday)
u: 8; wd: 8 (is not valid weekday)
u: 9; wd: 9 (is not valid weekday)

the way 7 wraps back around to 0? main character energy fr fr. 💀✨

👑 See also 👑

• c_encoding — retrieves the stored weekday value
• iso_encoding — retrieves ISO 8601 weekday value (public member function)

okay bye bestie, this page was brought to you by http://cppreference.com, dated 2024.06.10, for std::chrono::weekday::ok(3). slay and stay in range [0, 6] 💖🧚🌸