std::basic_string_view<CharT,Traits>::substr
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 + rcount), where rcount is the smaller of count and size() - pos.
Parameters
| pos | - | position of the first character |
| count | - | requested length |
Return value
View of the substring [pos, pos + rcount).
Exceptions
std::out_of_range if pos > size().
Complexity
Constant.
Example
#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
std::cout << data.substr(pos_t(1)) << '\n'; // BCDEF
std::cout << data.substr(pos_t(2), count_t(3)) << '\n'; // CDE
std::cout << data.substr(pos_t(4), count_t(42)) << '\n'; // EF
// count -> 2 == size() - pos == 6 - 4
try {
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)
See also
|
(C++17)
|
copies characters (public member function) |
|
(C++17)
|
find characters in the view (public member function) |
| returns a substring (public member function of std::basic_string<CharT,Traits,Allocator>) |
© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.
https://en.cppreference.com/w/cpp/string/basic_string_view/substr
