std::basic_string_view<CharT,Traits>::copy - cppreference.com (original) (raw)

| size_type copy( CharT* dest, size_type count, size_type pos = 0 ) const; | | (since C++17) (constexpr since C++20) | | ----------------------------------------------------------------------------- | | ------------------------------------- |

Copies the substring [pos, pos + rcount) to the character array pointed to by dest, where rcount is the smaller of count and size() - pos.

Equivalent to Traits::copy(dest, data() + pos, rcount).

[edit] Parameters

[edit] Return value

Number of characters copied.

[edit] Exceptions

std::out_of_range if pos > size().

[edit] Complexity

Linear in rcount.

[edit] Example

#include #include #include #include #include   int main() { constexpr std::basic_string_view source{"ABCDEF"}; std::array<char, 8> dest; std::size_t count{}, pos{};   dest.fill('\0'); source.copy(dest.data(), count = 4); // pos = 0 std::cout << dest.data() << '\n'; // ABCD   dest.fill('\0'); source.copy(dest.data(), count = 4, pos = 1); std::cout << dest.data() << '\n'; // BCDE   dest.fill('\0'); source.copy(dest.data(), count = 42, pos = 2); // ok, count -> 4 std::cout << dest.data() << '\n'; // CDEF   try { source.copy(dest.data(), count = 1, pos = 666); // throws: pos > size() } catch (std::out_of_range const& ex) { std::cout << ex.what() << '\n'; } }

Output:

ABCD BCDE CDEF basic_string_view::copy: __pos (which is 666) > __size (which is 6)

[edit] See also

| | returns a substring (public member function) [edit] | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | copies characters (public member function of std::basic_string<CharT,Traits,Allocator>) [edit] | | | copies a range of elements to a new location (function template) [edit] | | | copies one buffer to another (function) [edit] |