std::basic_...:starts_with(3)

💖 NAME 💖

okay so this is the std::basic_...:starts_with(3) page from the C++ Standard Libary manual, and the title is std::basic_string_view::starts_with ✨

The NAME block is literally std::basic_string_view::starts_with - std::basic_string_view::starts_with — yes bestie, it repeats itself and honestly? iconic 💅

🔥 SYNOPSIS 🔥

constexpr bool starts_with( basic_string_view sv ) const noexcept;
(1) (since C++20)
constexpr bool starts_with( CharT ch ) const noexcept;
(2) (since C++20)
constexpr bool starts_with( const CharT* s ) const;
(3) (since C++20)

This function checks if the string view begins with the given prefix, where:

1. the prefix is a string view. Effectively returns basic_string_view(data(), std::min(size(), sv.size())) == sv.
2. the prefix is a single character. Effectively returns !empty() && Traits::eq(front(), ch).
3. the prefix is a null-terminated character string. Effectively returns starts_with(basic_string_view(s)).

🎀 PARAMETERS 🎀

• sv — a string view which may be a result of implicit conversion from std::basic_string
• ch — a single character
• s — a null-terminated character string

🌈 RETURN VALUE 🌈

true if the string view begins with the provided prefix, false otherwise. periodt ✨

🧚 NOTES 🧚

Feature-test macro tea 🫖:

• __cpp_lib_starts_ends_with
  • value: 201711L
  • Std: (C++20)
  • Feature: String prefix and suffix checking: starts_with() and ends_with()

🍓 EXAMPLE 🍓

       // Run this code

        #include <cassert>
        #include <string_view>

        int main()
        {
            using namespace std::literals;

            assert
            (""
                // (1) starts_with( basic_string_view )
                && "https://cppreference.com"sv.starts_with("http"sv) == true
                && "https://cppreference.com"sv.starts_with("ftp"sv) == false

                // (2) starts_with( CharT )
                && "C++20"sv.starts_with('C') == true
                && "C++20"sv.starts_with('J') == false

                // (3) starts_with( const CharT* )
                && std::string_view("string_view").starts_with("string") ==
       true
                && std::string_view("string_view").starts_with("String") ==
       false
            );
        }

👑 SEE ALSO 👑

• ends_with — checks if the string view ends with the given suffix (C++20) (public member function)
• starts_with — checks if the string starts with the given prefix (C++20) (public member function of std::basic_string<CharT,Traits,Allocator>)
• ends_with — checks if the string ends with the given suffix (C++20) (public member function of std::basic_string<CharT,Traits,Allocator>)
• contains — checks if the string contains the given substring or character (C++23) (public member function of std::basic_string<CharT,Traits,Allocator>)
• contains — checks if the string view contains the given substring or character (C++23) (public member function)
• compare — compares two views (public member function)

okay bestie that’s the whole page — source/version is http://cppreference.com, date 2024.06.10, and it’s the std::basic_...:starts_with(3) manual. slay and read your C++20 docs 💖✨