std::char_traits<char>:: find, std::char_traits<wchar_t>:: find, std::char_traits<char8_t>:: find, std::char_traits<char16_t>:: find, std::char_traits<char32_t>:: find

From cppreference.com
static const char_type *
find ( const char_type * ptr, std:: size_t count, const char_type & ch ) ;
(constexpr since C++17)

Searches for character ch within the first count characters of the sequence pointed to by ptr .

See CharTraits for the general requirements on character traits for X::find .

Parameters

ptr - pointer to a character string to search
count - the number of characters to analyze
ch - the character to search for

Return value

A pointer to the first character in the range specified by [ ptr , ptr + count ) that compares equal to ch , or a null pointer if not found.

Complexity

Linear in count .