In C++, the end method in the multiset class is a part of the Standard Template Library (STL). Its purpose is to provide an iterator pointing to the element after the last element in the multiset container. This function is valuable for establishing the boundaries of the container, enabling operations like iteration, comparison, and determining the range of elements within the multiset container.
Note:- This is a placeholder. No element exists in this location, and attempting to access it is undefined behavior.
Syntax:
It has the following syntax:
iterator end(); //until C++ 11
iterator end() const; //until C++ 11
iterator end() noexcept; //since C++ 11
iterator end() const noexcept; //since C++ 11
In this format,
- Argument: It does not accept any argument.
- Output: It provides an iterator pointing to the final element of the multiset.
Complexity Analysis
If we wish to execute any operation with the multiset end method, it operates in constant time complexity, denoted as O(1).
Simple C++ Multiset end function Example
Let's consider an illustration to showcase the multiset end method, focusing on string data types in C++.
Example
#include <iostream>
#include <set>
using namespace std; //using standard namespace
int main () //main function
{
multiset<string> mymultiset = {"Java", "C++", "Java", "C++"};
// display content:
for (multiset<string>::iterator it=mymultiset.begin(); it!=mymultiset.end(); ++it)
cout << *it<< '\n';
return 0;
}
Output:
C++
C++
Java
Java
Explanation:
In the preceding example, we establish a multiset of strings and set it up with multiple values. When employing a for loop, we have the capability to cycle through from the begin method to the end method. The begin method denotes the initial element of the string, while the end method signifies the position immediately following the final element. While iterating through the multiset, every element is displayed until the iterator hits the end method. As a result, the output showcases all the present elements in a sorted manner, underscoring the exclusive utilization of the end method as the termination limit.
C++ Multiset end Function Example using for-each loop
Let's explore a basic illustration of iterating through the multiset using a range-based for loop in C++.
Example
#include <iostream>
#include <set>
using namespace std; //using standard namespace
int main() //main function
{
multiset<int> c;
c.insert(5);
c.insert(2);
c.insert(1);
c.insert(1);
c.insert(0);
c.insert(0);
c.insert(2);
multiset<int>::iterator i = c.begin();
while (i != c.end())
cout << *i++ << " ";
cout << endl;
}
Output:
0 0 1 1 2 2 5
Explanation:
In this instance, we've established a multiset that holds integer values. Subsequently, the insert function is employed to add specific values to the multiset. Following this, a while loop is initiated, continuing until it reaches the end function. Within the loop, the iterator is displayed, and upon completion, the loop is exited. Ultimately, the output is displayed on the screen.
C++ Multiset end Function Example using While Loop
Let's consider an instance where we iterate through the multiset using a while loop in the C++ programming language.
Example
#include <iostream>
#include <set>
#include <string>
int main() //main function
{
using namespace std; //using standard namespace
multiset<string> mymultiset = { "Robert","Peter","Johnson","Stuart","Rozzer" };
cout<<"Elements of mymultiset are: "<<endl;
multiset<string>::const_iterator it; // declare an iterator
it = mymultiset.begin(); // assign it to the start of the multiset
while (it != mymultiset.end()) // while it hasn't reach the end
{
cout << *it << "\n";
// print the value of the element icpp tutorials to
++it; // iteration to the next element
}
cout << endl;
}
Output:
Elements of mymultiset are:
Johnson
Peter
Robert
Rozzer
Stuart
Explanation:
In the previous illustration, we have generated a multiset that includes string values and afterward employed a for loop with an iterator for navigating through it. The loop commences from the begin method, indicating the initial element, and proceeds until it hits the end method, symbolizing the location right after the final element. The iterator is incremented before use in each iteration to display all elements in an ordered manner. Hence, the end method serves to delineate the limit of the multiset, producing an iterator that denotes a position beyond the ultimate element of mymultiset.
C++ Example to find the elements using the begin and end function
Let's consider a basic scenario where we have invoked the end function on integer values in C++.
Example
#include <iostream>
#include <string>
#include <set>
using namespace std; //using standard namespace
int main () //main function
{
int val;
multiset<int> c = {10,20,10,20,40,50};
cout<<"Enter value to find: ";
cin>>val;
auto result = c.find(val);
//find until the end of the multiset elements
if (result != c.end()) {
cout << "Element found: "<< *result;
cout << endl;
} else {
cout << "Element not found." << endl;
}
return 0;
}
Output:
Enter value to find: 60
Element not found.
Enter value to find: 20
Element found: 20
Explanation:
In this particular instance, we've established a multiset labeled as c, encompassing a variety of integer values. Following this, the program requests input for the specific number we aim to locate within the multiset. Subsequently, we employ the find method to ascertain the presence of the element within the multiset. Utilizing the end function provides us with an iterator pointing to the element preceding the final one in the multiset.
When we search for the value 60 in the multiset, it is compared against the end function, leading to the output "element is not found". Conversely, when searching for the value 20, it is compared with the end function, resulting in the message that the element has been found.
Features of the Multiset end Function
There are several features of the multiset end function in C++. Some of the main features are as follows:
- The multiset end function is mainly utilized to return an iterator thacpp tutorials just after the last element in the multiset, not to an original element.
- When we need to call the end function on a const multiset, it returns a const_iterator. Otherwise, it will return a regular iterator.
- If we want to perform any operation or task using the multiset end function in C++, it takes only constant time, O(1), to complete those tasks.
- If we use the end function in the empty multiset, it works similarly to the begin function. If we use this function in a non-empty multiset, it marks the boundary beyond the last element of the container.
- It is commonly utilized as the upper limit in loops to traverse the complete multiset in C++.
- If we want to insert elements in the multiset container, it does not invalidate iterators to existing elements. However, it erases an element that is pointed to by an iterator and invalidates that iterator.
Conclusion
In summary, the multiset::end function within C++ serves as a fundamental and straightforward technique within the multiset container. This function is frequently employed to yield an iterator indicating the limit immediately following the final element in the multiset. Its primary purposes include setting boundaries for iterations, verifying search outcomes, and ensuring secure navigation through elements. Despite its inability to be dereferenced, it plays a crucial role in terminating loops and facilitating operations based on iterators. All in all, the multiset end function stands as a basic yet crucial tool for effectively handling and traversing a multiset.
Frequently Asked Questions
1) What is the multiset end function in C++?
The multiset::end function within C++ serves as a fundamental and straightforward technique in the multiset container. It is frequently used to generate an iterator that denotes the limit immediately following the final element in the multiset.
The dissimilarity between the 'end' and 'cend' functions in C++ lies in the fact that 'end' returns an iterator pointing to the element past the last element in a container, allowing modification of the elements. On the other hand, 'cend' returns a constant iterator pointing to the same position, restricting any modifications to the elements in the container.
The primary contrast between the end and cend functions in C++ lies in their return types. The end function provides a non-const iterator, permitting element modifications. In contrast, the cend function returns a const_iterator, enabling only read access. It is advisable to utilize the cend function for const multisets or scenarios where element modification is unnecessary.
3) Can reverse iterators be used with the end method?
Yes, the 'end' function can be applied with reverse iterators. By combining the 'end' function with the rbegin method, we can point to the position just before the first element in reverse sequence.
No, the insertion of a new element does not affect the value returned by the end function in C++.
Yes. As we add an element to the multiset container, the end iterator shifts to accommodate the container's expansion.
5) Will removing an element impact the iterator returned by the end function in C++?
When removing an element from a container in C++, it may cause changes to the internal organization, yet usually the iterator pointing just beyond the end will still be valid. Nonetheless, the iterator referring to the deleted element will no longer be valid.
When we invoke the end function on an empty multiset in C++, it will return an iterator pointing to the theoretical element that follows the last element in the multiset.
When removing an element from a container in C++, it may cause changes to the internal structure, yet generally, the iterator pointing beyond the end remains valid. Nonetheless, the iterator referring to the deleted element becomes invalid.
