How to Access the First Element of a Deque in C++?
In C++, deques also called double-ended queues are sequence containers that can perform insertions and deletions on both ends. In this article, we will learn how to access the first element of a deque in C++.
Example:
Input: myDeque = {1,2,3,4,5} Output: Deque Elements: 1 2 3 4 5 First Element: 1
Accessing the First Element of a Deque in C++
To access the first element of a std::deque in C++, we can use the std::deque::front() method which returns a reference to the first element of the deque. This function is suitable for accessing and manipulating the first element without modifying the deque’s structure.
Syntax
deque_name.front();
Here:
- deque_name: Denotess the deque container.
- front(): This denotes the function used to access the first element of the deque.
C++ Program to Access the First Element of a Deque
The below program demonstrates how we can access the first element of a deque in C++.
// C++ Program to illustrates how to access the first
// element of a deque
#include <deque>
#include <iostream>
using namespace std;
int main()
{
// Initializing a deque
deque<int> dq = { 1, 2, 3, 4, 5 };
// Printing deque elements
cout << "Deque Elements:";
for (int num : dq) {
cout << " " << num;
}
cout << endl;
// Accessing the first element using front()
int frontElement = dq.front();
// Printing the first element
cout << "First Element: " << frontElement << endl;
return 0;
}
Output
Deque Elements: 1 2 3 4 5 First Element: 1
Time Complexity: O(1)
Auxilliary Space: O(1)
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