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Showing content from https://en.cppreference.com/w/cpp/language/../utility/../string/basic_string_view/starts_with.html below:

std::basic_string_view<CharT,Traits>::starts_with - cppreference.com

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)

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)).

[edit] 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 [edit] Return value

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

[edit] Notes [edit] Example

#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
    );
}

[edit] See also checks if the string view ends with the given suffix
(public member function) [edit] checks if the string starts with the given prefix
(public member function of std::basic_string<CharT,Traits,Allocator>) [edit] checks if the string ends with the given suffix
(public member function of std::basic_string<CharT,Traits,Allocator>) [edit] checks if the string contains the given substring or character
(public member function of std::basic_string<CharT,Traits,Allocator>) [edit] checks if the string view contains the given substring or character
(public member function) [edit] compares two views
(public member function) [edit]

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