deque::cbegin
deque::cbegin is used to return a const iterator pointing to the first element in the container. We cannot use this to modify the contents the iterator points to.
Syntax:
const_iterator cbegin();
Parameters: None
Return Value: A const_iterator to the beginning of the sequence.
Iterator Validity: There is no change in Iterator Validity
Header File:
<deque>
Exceptions: It never throws exceptions
Example:
C++
// C++ program to demonstrate deque::cbegin #include <deque> #include <iostream> using namespace std; // Driver code int main() { // Declaration of Deque deque<int> GFG = { 1, 2, 3, 4, 5 }; cout << "Elements in Deque Container are : "; for (auto it = GFG.cbegin(); it != GFG.cend(); ++it) { cout << *it << " "; } cout << endl; return 0; } |
Output:
Elements in Deque Container are : 1 2 3 4 5
- Time Complexity – O(1)
- Space Complexity – O(1)
Difference Between deque::cbegin and deque::assign in C++
Deque or Double-ended queues are sequence containers with the feature of expansion and contraction on both ends. They are similar to vectors, but are more efficient in the case of insertion and deletion of elements at the end, and also the beginning. Unlike vectors, contiguous storage allocation may not be guaranteed. Here we will see the difference between deque::assign and deque::at in C++.