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std::deque::at(3) C++ Standard Libary std::deque::at(3) NAME std::deque::at - std::deque::at Synopsis reference at( size_type pos ); (1) const_reference at( size_type pos ) const; (2) Returns a reference to the element at specified location pos, with bounds checking. If pos is not within the range of the container, an exception of type std::out_of_range is thrown. Parameters pos - position of the element to return Return value Reference to the requested element. Exceptions std::out_of_range if pos >= size(). Complexity Constant. Example // Run this code #include <iostream> #include <deque> #include <stdexcept> #ifdef __GNUG__ [[gnu::noinline]] #endif unsigned int runtime_six() // Emulate runtime input { return 6u; } int main() { std::deque<int> data = {1, 2, 4, 5, 5, 6}; // Set element 1 data.at(1) = 88; // Read element 2 std::cout << "Element at index 2 has value " << data.at(2) << '\n'; std::cout << "data size = " << data.size() << '\n'; try { // Set element 6, where the index is determined at runtime data.at(runtime_six()) = 666; } catch (std::out_of_range const& exc) { std::cout << exc.what() << '\n'; } // Print final values std::cout << "data:"; for (int elem : data) std::cout << ' ' << elem; std::cout << '\n'; } Possible output: Element at index 2 has value 4 data size = 6 deque::_M_range_check: __n (which is 6)>= this->size() (which is 6) data: 1 88 4 5 5 6 See also operator[] access specified element (public member function) http://cppreference.com 2024.06.10 std::deque::at(3)
NAME | Synopsis | Parameters | Return value | Exceptions | Complexity | Example | Possible output: | See also
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