From cppreference.com
constexprsize_typefind_first_of(basic_string_viewv,size_typepos=0)constnoexcept; (1) (since C++17)constexprsize_typefind_first_of(CharTch,size_typepos=0)constnoexcept; (2) (since C++17)constexprsize_typefind_first_of(constCharT*s,size_typepos,size_typecount)const; (3) (since C++17)constexprsize_typefind_first_of(constCharT*s,size_typepos=0)const; (4) (since C++17)Finds the first character equal to any of the characters in the given character sequence.
1) Finds the first occurrence of any of the characters of v in this view, starting at position pos.
2) Equivalent to find_first_of(basic_string_view(std::addressof(ch),1),pos).
3) Equivalent to find_first_of(basic_string_view(s,count),pos).
4) Equivalent to find_first_of(basic_string_view(s),pos).
Parameters
v - view to search for pos - position at which to start the search count - length of the string of characters to search for s - pointer to a string of characters to search for ch - character to search for Return value
Position of the first occurrence of any character of the substring, or
if no such character is found.
Complexity
O(
* v.
) at worst.
Example
Run this code
#include<string_view>usingnamespacestd::literals;constexprautoN=std::string_view::npos;constexprboolis_white_space(constcharc){return" \t\n\f\r\v"sv.find_first_of(c)!=N;};static_assert(1=="alignas"sv.find_first_of("klmn"sv)&&// └─────────────────────────┘N=="alignof"sv.find_first_of("wxyz"sv)&&//3=="concept"sv.find_first_of("bcde"sv,/* pos= */1)&&// └───────────────────────┘N=="consteval"sv.find_first_of("oxyz"sv,/* pos= */2)&&//6=="constexpr"sv.find_first_of('x')&&// └─────────────────────┘N=="constinit"sv.find_first_of('x')&&//6=="const_cast"sv.find_first_of('c',/* pos= */4)&&// └──────────────────────┘N=="continue"sv.find_first_of('c',/* pos= */42)&&//5=="co_await"sv.find_first_of("cba",/* pos= */4)&&// └───────────────────────┘7=="decltype"sv.find_first_of("def",/* pos= */2,/* count= */2)&&// └────────────────────┘N=="decltype"sv.find_first_of("def",/* pos= */2,/* count= */1)&&//is_white_space(' ')&&is_white_space('\r')&&!is_white_space('\a'));intmain(){}See also
find characters in the view
(public member function)
find the last occurrence of a substring
(public member function)
find last occurrence of characters
(public member function)
find first absence of characters
(public member function)
find last absence of characters
(public member function)
find first occurrence of characters
(public member function of std::basic_string<CharT,Traits,Allocator>)