Difference between revisions of "cpp/string/basic string/at"
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< cpp | string | basic string
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Revision as of 04:16, 4 May 2021
reference at( size_type pos ); |
(until C++20) | |
| constexpr reference at( size_type pos ); |
(since C++20) | |
const_reference at( size_type pos ) const; |
(until C++20) | |
| constexpr const_reference at( size_type pos ) const; |
(since C++20) | |
Returns a reference to the character at specified location pos. Bounds checking is performed, exception of type std::out_of_range will be thrown on invalid access.
Contents |
Parameters
| pos | - | position of the character to return |
Return value
Reference to the requested character.
Exceptions
Throws std::out_of_range if pos >= size().
Complexity
Constant.
Example
Run this code
#include <stdexcept> #include <iostream> #include <string> int main() { std::string s("message"); // for capacity s = "abc"; s.at(2) = 'x'; // ok std::cout << s << '\n'; std::cout << "string size = " << s.size() << '\n'; std::cout << "string capacity = " << s.capacity() << '\n'; try { // This will throw since the requested offset is greater than the current size. s.at(3) = 'x'; } catch (std::out_of_range const& exc) { std::cout << exc.what() << '\n'; } }
Possible output:
abx string size = 3 string capacity = 7 basic_string::at
See also
| accesses the specified character (public member function) | |
| accesses the specified character with bounds checking (public member function of std::basic_string_view<CharT,Traits>)
|
