std::basic_string<CharT,Traits,Allocator>::contains

`constexpr bool contains( std::basic_string_view<CharT,Traits> sv ) const noexcept;`	(1)	( C++23)
`constexpr bool contains( CharT ch ) const noexcept;`	(2)	( C++23)
`constexpr bool contains( const CharT* s ) const;`	(3)	( C++23)

, . :

1) sv ( std::basic_string).

2) ch.

3) s, .

return find(x) != npos;, x .

sv		, `std::basic_string`
ch
s		,

true, , false .


`__cpp_lib_string_contains`	`202011L`	(C++23)	`contains`

#include <iomanip>
#include <iostream>
#include <string>
#include <string_view>
#include <type_traits>

template<typename SubstrType>
void test_substring(const std::string& str, SubstrType subs)
{
    constexpr char delim = std::is_scalar_v<SubstrType> ? '\'' : '\"';
    std::cout << std::quoted(str)
              << (str.contains(subs) ? "  "
                                     : "   ")
              << std::quoted(std::string{subs}, delim) << '\n';
}

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

    auto helloWorld = "hello world"s;

    test_substring(helloWorld, "hello"sv);
    test_substring(helloWorld, "goodbye"sv);
    test_substring(helloWorld, 'w');
    test_substring(helloWorld, 'x');
}

:

"hello world"  "hello"
"hello world"   "goodbye"
"hello world"  'w'
"hello world"   'x'

starts_with (C++20)	, (public -) []
ends_with (C++20)	, (public -) []
find	(public -) []
substr	(public -) []
contains (C++23)	, (public - `std::basic_string_view<CharT,Traits>`) []







(C++20)

(C++20)
(C++11)





(C++20)


/

(C++11)
(C++11)
(C++11)
(C++17)

cppreference.com

std::basic_string<CharT,Traits,Allocator>::contains