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std::basic_...starts_with(3) C++ Standard Libary std::basic_...starts_with(3) NAME std::basic_string::starts_with - std::basic_string::starts_with Synopsis constexpr bool starts_with( std::basic_string_view<CharT,Traits> sv ) const (1) (since C++20) noexcept; constexpr bool (2) (since C++20) starts_with( CharT ch ) const noexcept; constexpr bool (3) (since C++20) starts_with( const CharT* s ) const; Checks if the string begins with the given prefix. The prefix may be one of the following: 1) A string view sv (which may be a result of implicit conversion from another std::basic_string). 2) A single character ch. 3) A null-terminated character string s. All three overloads effectively return std::basic_string_view<CharT, Traits>(data(), size()).starts_with(x), where x is the parameter. Parameters sv - a string view which may be a result of implicit conversion from another std::basic_string ch - a single character s - a null-terminated character string Return value true if the string begins with the provided prefix, false otherwise. Notes Feature-test macro Value Std Feature __cpp_lib_starts_ends_with 201711L (C++20) String prefix and suffix checking: starts_with() and ends_with() Example // Run this code #include <cassert> #include <string> #include <string_view> int main() { using namespace std::literals; const auto str = "Hello, C++20!"s; assert ("" && str.starts_with("He"sv) // (1) && !str.starts_with("he"sv) // (1) && str.starts_with("He"s) // (1) implicit conversion string to string_view && !str.starts_with("he"s) // (1) implicit conversion string to string_view && str.starts_with('H') // (2) && !str.starts_with('h') // (2) && str.starts_with("He") // (3) && !str.starts_with("he") // (3) ); } See also ends_with checks if the string ends with the given suffix (C++20) (public member function) starts_with checks if the string view starts with the given prefix (C++20) (public member function of std::ba- sic_string_view<CharT,Traits>) ends_with checks if the string view ends with the given suffix (C++20) (public member function of std::ba- sic_string_view<CharT,Traits>) contains checks if the string contains the given substring or character (C++23) (public member function) contains checks if the string view contains the given substring or character (C++23) (public member function of std::ba- sic_string_view<CharT,Traits>) compare compares two strings (public member function) substr returns a substring (public member function) http://cppreference.com 2024.06.10 std::basic_...starts_with(3)
NAME | Synopsis | Parameters | Return value | Notes | Example | See also
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