std::ctype:...do_scan_not(3)

✨ NAME ✨

okay so this is the C++ Standard Library manual page for std::ctype::scan_not and std::ctype::do_scan_not. bestie, it’s the “scan until the mask says no” duo — one public, one protected virtual. periodt 💅

🎀 Synopsis 🎀

Defined in header <locale>.

public:
(1)
const CharT* scan_not( mask m, const CharT* beg, const CharT* end ) const;

protected:
(2)
virtual const CharT* do_scan_not( mask m, const CharT* beg, const CharT* end ) const;

• (1) — public member function, calls the protected virtual member function do_scan_not of the most derived class. slay ✨
• (2) — locates the first character in the character array [beg, end) that does not satisfy the classification mask m, that is, the first character c such that is(m, c) would return false. periodt.

🌸 Parameters 🌸

• m — mask to search for.
• beg — pointer to the first character in an array of characters to search.
• end — one past the end pointer for the array of characters to search.

bestie, end is one-past-the-end, not the last character — don’t get it twisted 💅

🦋 Return value 🦋

Pointer to the first character in [beg, end) that doesn’t satisfy the mask, or end if no such character was found. no cap, that’s it. ✨

🧚 Example 🧚

Run this code:

#include <clocale>
#include <iostream>
#include <iterator>
#include <locale>

int main()
{
    std::setlocale(LC_ALL, "en_US.utf8");
    std::wcout.imbue(std::locale("en_US.utf8"));
    auto& f = std::use_facet<std::ctype<wchar_t>>(std::wcout.getloc());

    // skip leading whitespace
    wchar_t s1[] = L"      \t\t\n  Кошка";
    const wchar_t* p1 = f.scan_not(std::ctype_base::space, std::begin(s1), std::end(s1));
    std::wcout << '\'' << p1 << "'\n";

    // skip leading digits
    wchar_t s2[] = L"123456789ネプネプ";
    const wchar_t* p2 = f.scan_not(std::ctype_base::digit, std::begin(s2), std::end(s2));
    std::wcout << '\'' << p2 << "'\n";
}

💖 Output 💖

'Кошка'
'ネプネプ'

🔍 See also 🔍

• scan_not — locates the first character in a sequence that fails given classification, using the classification table (public member function of std::ctype<char>).
• do_scan_is [virtual] — locates the first character in a sequence that conforms to given classification (virtual protected member function).

source: http://cppreference.com · version/date: 2024.06.10 · page: std::ctype:...do_scan_not(3) — mwah 💋🫶