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C++ Deque Library - at() Function
Description
The C++ function std::deque::at() returns a reference to the element present at location n in the deque.
Declaration
Following is the declaration for std::deque::at() function form std::deque header.
C++98
reference at (size_type n); const_reference at (size_type n) const;
Parameters
n − Position of the element in the deque.
Return value
Returns an element from specified location if n is valid deque index. If deque object is constant qualified then method returns constant reference otherwise non-constant reference.
Exceptions
If n is not valid index out_of_bound exception is thrown.
Time complexity
Constant i.e. O(1)
Example
The following example shows the usage of std::deque::at() function.
#include <iostream> #include <deque> using namespace std; int main(void) { deque<int> d = {1, 2, 3, 4, 5}; cout << "Contents of deque are" << endl; for (int i = 0; i < d.size(); ++i) cout << d.at(i) << endl; return 0; }
Let us compile and run the above program, this will produce the following result −
Contents of deque are 1 2 3 4 5
deque.htm
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