std::basic_string_view<CharT,Traits>::substr
From cppreference.com
< cpp | string | basic string view
constexpr basic_string_view substr( size_type pos = 0, size_type count = npos ) const; |
(since C++17) | |
Returns a view of the substring [
pos,
pos + rlen)
, where rlen
is the smaller of count and size() - pos.
Contents |
[edit] Parameters
pos | - | position of the first character |
count | - | requested length |
[edit] Return value
View of the substring [
pos,
pos + rlen)
.
[edit] Exceptions
std::out_of_range if pos > size().
[edit] Complexity
Constant.
[edit] Example
Run this code
#include <cstddef> #include <iostream> #include <stdexcept> #include <string_view> int main() { typedef std::size_t count_t, pos_t; constexpr std::string_view data{"ABCDEF"}; std::cout << data.substr() << '\n'; // ABCDEF, i.e. data[0, 5] that is [0, 6) std::cout << data.substr(pos_t(1)) << '\n'; // BCDEF, i.e. [1, 6) std::cout << data.substr(pos_t(2), count_t(3)) << '\n'; // CDE, i.e. [2, 2 + 3) std::cout << data.substr(pos_t(4), count_t(42)) << '\n'; // EF, i.e. [4, 6) try { [[maybe_unused]] auto sub = data.substr(pos_t(666), count_t(1)); // throws: pos > size() } catch (std::out_of_range const& ex) { std::cout << ex.what() << '\n'; } }
Possible output:
ABCDEF BCDEF CDE EF basic_string_view::substr: __pos (which is 666) > __size (which is 6)
[edit] See also
copies characters (public member function) | |
find characters in the view (public member function) | |
returns a substring (public member function of std::basic_string<CharT,Traits,Allocator> )
|