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

Since C++23

Checks if the string contains the given substring. The substring may be one of the following:

# Declarations

constexpr bool
contains( std::basic_string_view<CharT,Traits> sv ) const noexcept;

(since C++23)

constexpr bool
contains( CharT ch ) const noexcept;

(since C++23)

constexpr bool
contains( const CharT* s ) const;

(since C++23)

# Parameters

# Return value

true if the string contains the provided substring, false otherwise.

# Notes

Feature-test macro Value Std Feature __cpp_lib_string_contains 202011L (C++23) contains functions

# Example

#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) ? " contains "
                                     : " does not contain ")
              << 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');
}

# See also