In C++, the deque, short for double-ended queue, serves as a container class within the Standard Template Library (STL). It facilitates rapid insertion and removal of elements at both the front and back of the deque.
In C++, the Deque end method is frequently used to retrieve an iterator pointing to the "past-the-end" element of the deque. When the deque is empty, the end function returns the same result as the begin function. The "past-the-end" element is a reference point beyond the last element, serving as the endpoint for forward iteration.
Syntax
It has the following syntax:
iterator end() noexcept;
const_iterator end() const noexcept;
In this particular syntax,
- it lacks any parameters.
It provides an iterator pointing to the element after the last one in the deque. When the deque is immutable, it also furnishes the const_iterator.
C++ Deque end Simple Example
Let's consider a scenario to demonstrate the Deque end method in C++.
Example
#include <iostream>
#include<deque>
using namespace std; //using standard namespace
int main() //main function
{
deque<int> k={10,20,30,40,50};
deque<int>::iterator itr=k.begin();
while(itr!=k.end())
{
cout<<*itr;
cout<<" ";
++itr;
}
return 0;
}
Output:
10 20 30 40 50
Explanation:
In this instance, we've selected a deque containing integer values and navigated through it utilizing an iterator. Subsequently, we've employed the begin method to obtain the iterator pointing to the initial element, and the end method to indicate the position right beyond the final element. As a result, the iteration continues until the iterator reaches the end function, effectively displaying all elements of the deque sequentially.
C++ Example to Accessing the Last Element Using the end function
Let's consider a scenario to demonstrate how to retrieve the final element by utilizing the end function in the C++ programming language.
Example
#include <iostream>
#include <deque>
using namespace std; //using standard namespace
int main() { //main function
deque<string> dq = {"C++", "Java", "Python", "C#", "DSA"};
auto it = dq.end();
--it; // Move one step back to point to the last element
cout << "Last element of the deque is: " << *it << endl;
return 0;
}
Output:
Last element of the deque is: DSA
Explanation:
In this instance, a deque containing strings was established, and the end method was applied to obtain an iterator pointing beyond the final element. Subsequently, the iterator was decremented using --it to position it at the true final element, ultimately revealing the value "DSA".
C++ STL Algorithm find function Example Using the end function
Let's consider a scenario to demonstrate the utilization of the STL Algorithm find method in C++ along with the end function.
Example
#include <iostream>
#include <deque>
#include <algorithm> s//using algorithm header file
using namespace std; //using standard namespace
int main() { //main function
deque<int> dq = {15, 20, 25, 30, 25};
auto it = find(dq.begin(), dq.end(), 25);
if (it != dq.end())
cout << "Element is found in the Deque: " << *it << endl;
else
cout << "Element not found!" << endl;
return 0;
}
Output:
Element is found in the Deque: 25
Explanation:
In this instance, we have generated a deque containing integer values and applied the find function to search for the number 25 using the begin and end functions. When the returned iterator does not match the dq.end function, it indicates that the element exists in the deque, and the located value is then showcased on the output screen.
Features of the Deque end Function in C++
There are several features of the Deque end function in C++. Some of the main features are as follows:
- The deque end function is commonly utilized with several iteration functions, such as a loop. It can also be utilized with the combination of the begin function to traverse the whole deque.
- It does nocpp tutorial to a valid element in C++.
- It is very useful with several STL Algorithms, such as find, sort, and many others, which need the range iterators.
- It helps to prevent out-of-bounds errors when we iterate through the deque container.
- It does not take any arguments, and it only returns the iterator position.
- It has a constant time complexity, i.e., (O(1)).
Conclusion
In summary, the C++ deque end method proves to be a straightforward and efficient technique within the deque container. It is frequently employed to provide an iterator that points to the element just beyond the last one in the deque. This method is valuable in establishing ranges for various activities like iteration, modification, and algorithmic processes. It is typically paired with the begin method and is not intended for standalone usage in the program. The end function's constant time complexity, exception handling capabilities, and ability to work with const iterators all contribute to its reputation as a dependable and efficient feature in C++.
C++ Deque end function FAQs
The deque end function in the C++ programming language returns an iterator pointing to the element past the last element in the deque container.
In C++, the end function in deque gives back an iterator pointing to the position immediately after the final element (referred to as the "past-the-last" element) within a deque. Its primary purpose is to establish the concluding boundary for iteration and algorithmic tasks.
Yes, is it possible to utilize the end function within C++ STL algorithms?
In C++, the end function is commonly used with various algorithms such as sort, find, for_each, and numerous others.
The primary variance between the end and rend functions in the C++ programming language lies in their behavior regarding iterators.
In C++, the primary contrast between the end and rend functions lies in their respective roles. The end function indicates the end limit for forward iteration, while the rend function denotes the end limit for reverse iteration.
4) Is it permissible to dereference the iterator produced by the end function in C++?
No, attempting to access the value pointed to by the iterator obtained from the end function can result in undefined behavior as it does not point to a valid element within the deque in C++.
#include <iostream>
#include <deque>
#include <algorithm> s//using algorithm header file
using namespace std; //using standard namespace
int main() { //main function
deque<int> dq = {15, 20, 25, 30, 25};
auto it = find(dq.begin(), dq.end(), 25);
if (it != dq.end())
cout << "Element is found in the Deque: " << *it << endl;
else
cout << "Element not found!" << endl;
return 0;
}
In C++ programming, a key contrast between the end and begin functions lies in the fact that end points to the element beyond the last one in the deque, while begin points to the initial element of the deque container.
6) Is it permissible to employ the end function with an immutable deque in the C++ programming language?
Yes, the end function can be applied to a constant deque in C++. Using end with a constant deque will yield a const_iterator which can be employed for iterating through the elements.
