Return the starting position of the first occurrence of the specified substring, if such a substring can be found in this string (on or after the optionally specified position if such a position is specified) using CHAR_TRAITS::eq to compare characters, and return npos otherwise.
Declared in <bslstl_string.h>
size_type
find(
basic_string const& substring,
size_type position = 0) const noexcept;