std::basic_string<CharT,Traits,Allocator>::contains
From cppreference.com
constexpr bool contains( std::basic_string_view<CharT,Traits> sv )
const noexcept;
|
(1) | (since C++23) |
constexpr bool contains( CharT c ) const noexcept;
|
(2) | (since C++23) |
constexpr bool 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:
1) a string view
sv (which may be a result of implicit conversion from another std::basic_string).2) a single character
c.3) a null-terminated character string
s.All three overloads effectively return find(x) != npos, where x is the parameter.
Parameters
| sv | - | a string view which may be a result of implicit conversion from another std::basic_string
|
| c | - | a single character |
| s | - | a null-terminated character string |
Return value
true if the string contains the provided substring, false otherwise.
Example
Run this code
#include <iostream>
#include <string_view>
#include <string>
template <typename PrefixType>
void test_substring_print(const std::string& str, PrefixType prefix)
{
std::cout << '\'' << str << "' contains '" << prefix << "': " <<
str.contains(prefix) << '\n';
}
int main()
{
std::boolalpha(std::cout);
auto helloWorld = std::string("hello world");
test_substring_print(helloWorld, std::string_view("hello"));
test_substring_print(helloWorld, std::string_view("goodbye"));
test_substring_print(helloWorld, 'h');
test_substring_print(helloWorld, 'x');
}
Output:
'hello world' contains 'hello': true
'hello world' contains 'goodbye': false
'hello world' contains 'h': true
'hello world' contains 'x': false
See also
(C++20) |
checks if the string starts with the given prefix (public member function) |
(C++20) |
checks if the string ends with the given suffix (public member function) |
| finds the first occurrence of the given substring (public member function) | |
| returns a substring (public member function) |