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constexprbool contains(std::basic_string_view<CharT,Traits> sv)constnoexcept; | (1) | (since C++23) |
constexprbool contains( CharT ch)constnoexcept; | (2) | (since C++23) |
constexprbool contains(const CharT* s)const; | (3) | (since C++23) |
Checks if the string contains the given substring. The substring may be one of the following:
std::basic_string).All three overloads are equivalent toreturn find(x)!= npos;, wherex is the parameter.
Contents |
| sv | - | a string view which may be a result of implicit conversion from anotherstd::basic_string |
| ch | - | a single character |
| s | - | a null-terminated character string |
true if the string contains the provided substring,false otherwise.
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_string_contains | 202011L | (C++23) | contains functions |
#include <iomanip>#include <iostream>#include <string>#include <string_view>#include <type_traits> template<typename SubstrType>void test_substring(conststd::string& str, SubstrType subs){constexprchar 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(){usingnamespace 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');}
Output:
"hello world" contains "hello""hello world" does not contain "goodbye""hello world" contains 'w'"hello world" does not contain 'x'
(C++20) | checks if the string starts with the given prefix (public member function)[edit] |
(C++20) | checks if the string ends with the given suffix (public member function)[edit] |
| finds the first occurrence of the given substring (public member function)[edit] | |
| returns a substring (public member function)[edit] | |
(C++23) | checks if the string view contains the given substring or character (public member function of std::basic_string_view<CharT,Traits>)[edit] |
