std::basic_string_view<CharT,Traits>::starts_with

 

C++

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Language support library

Concepts library (C++20)

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Technical Specifications

 

Strings library

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Classes

basic_string

basic_string_view (C++17)

char_traits

 

std::basic_string_view

Member functions basic_string_view::basic_string_view basic_string_view::operator= Iterators basic_string_view::beginbasic_string_view::cbegin basic_string_view::endbasic_string_view::cend basic_string_view::rbeginbasic_string_view::crbegin basic_string_view::rendbasic_string_view::crend Element access basic_string_view::at basic_string_view::operator[] basic_string_view::front basic_string_view::back basic_string_view::data Capacity basic_string_view::sizebasic_string_view::length basic_string_view::max_size basic_string_view::empty Modifiers basic_string_view::remove_prefix basic_string_view::remove_suffix basic_string_view::swap

Operations basic_string_view::copy basic_string_view::substr basic_string_view::compare basic_string_view::starts_with (C++20) basic_string_view::ends_with (C++20) basic_string_view::find basic_string_view::rfind basic_string_view::find_first_of basic_string_view::find_last_of basic_string_view::find_first_not_of basic_string_view::find_last_not_of Constants basic_string_view::npos Non-member functions operator==operator!=operator<operator>operator<=operator>= operator<< operator""sv Helper classes hash<std::string_view>hash<std::wstring_view>hash<std::u16string_view>hash<std::u32string_view>

 

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

Checks if the string view begins with the given prefix, where

1) the prefix is a string view. Effectively returns size() >= x.size() && compare(0, x.size(), x) == 0

2) the prefix is a single character. Effectively returns !empty() && Traits::eq(front(), x)

3) the prefix is a C-style string. Effectively returns starts_with(basic_string_view(x))

Parameters

x

-

a character sequence or a single character to compare to the start of the string view

Return value

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

See also

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