How to delete last element from a List in C++ STL - GeeksforGeeks

18 Jan, 2019
Given a List, the task is to remove the last element from this List in C++.
Examples:
Input: list = [10 20 30 70 80 90 100 40 50 60]
Output: 10 20 30 40 50 60 70 80 90

Input: list = [1 2 3 4 5]
Output: 1 2 3 4

Lists are a type of associative containers in which each element has to be unique because the value of the element identifies it. The value of the element cannot be modified once it is added to the list, though it is possible to remove and add the modified value of that element.
The last element of the List can be deleted by by passing its iterator.
Syntax:
iterator erase (const_iterator positionOfElementToBeDeleted);

Approach: One can easily delete the last element by passing its iterator to the erase function. To reach the iterator which points to the last element, there are two ways:
Method 1:prev(listInt.end())Below is the implementation of the above approach:Program 1:// C++ program to delete last element// of a List by passing its iterator  #include <iostream>#include <list>using namespace std;  // Function to print the listvoid printList(list<int> mylist){      // Get the iterator    list<int>::iterator it;      // printing all the elements of the list    for (it = mylist.begin(); it != mylist.end(); ++it)        cout << ' ' << *it;    cout << '\n';}  // Function to delete last element of list// using method 1void deleteByMethod1(list<int> mylist){      // printing all the elements of the list    cout << "\nList originally: ";    printList(mylist);      // Get the iterator    list<int>::iterator it;      // Get the positionOfElementToBeDeleted    // using method 1    it = prev(mylist.end());      // Erase the last element    // currently pointed by the iterator    mylist.erase(it);      // printing all the elements of the list    cout << "List after deletion: ";    printList(mylist);}  // Driver codeint main(){    list<int> mylist;      // Get the list    for (int i = 1; i < 10; i++)        mylist.push_back(i * 10);      // Method 1 to get positionOfElementToBeDeleted    deleteByMethod1(mylist);      return 0;}Output:List originally:  10 20 30 40 50 60 70 80 90
List after deletion:  10 20 30 40 50 60 70 80
Method 2:list::iterator it = listInt.end(); 
--it;
Below is the implementation of the above approach:Program 2:// C++ program to delete last element// of a List by passing its iterator  #include <iostream>#include <list>using namespace std;  // Function to print the listvoid printList(list<int> mylist){      // Get the iterator    list<int>::iterator it;      // printing all the elements of the list    for (it = mylist.begin(); it != mylist.end(); ++it)        cout << ' ' << *it;    cout << '\n';}  // Function to delete last element of list// using method 2void deleteByMethod2(list<int> mylist){      // printing all the elements of the list    cout << "\nList originally: ";    printList(mylist);      // Get the iterator    list<int>::iterator it;      // Get the positionOfElementToBeDeleted    // using method 2    it = --mylist.end();      // Erase the last element    // currently pointed by the iterator    mylist.erase(it);      // printing all the elements of the list    cout << "List after deletion: ";    printList(mylist);}  // Driver codeint main(){    list<int> mylist;      // Get the list    for (int i = 1; i < 10; i++)        mylist.push_back(i * 10);      // Method 2 to get positionOfElementToBeDeleted    deleteByMethod2(mylist);      return 0;}Output:List originally:  10 20 30 40 50 60 70 80 90
List after deletion:  10 20 30 40 50 60 70 80
My Personal Notes
arrow_drop_upSave
Method 1:prev(listInt.end())Below is the implementation of the above approach:Program 1:// C++ program to delete last element// of a List by passing its iterator  #include <iostream>#include <list>using namespace std;  // Function to print the listvoid printList(list<int> mylist){      // Get the iterator    list<int>::iterator it;      // printing all the elements of the list    for (it = mylist.begin(); it != mylist.end(); ++it)        cout << ' ' << *it;    cout << '\n';}  // Function to delete last element of list// using method 1void deleteByMethod1(list<int> mylist){      // printing all the elements of the list    cout << "\nList originally: ";    printList(mylist);      // Get the iterator    list<int>::iterator it;      // Get the positionOfElementToBeDeleted    // using method 1    it = prev(mylist.end());      // Erase the last element    // currently pointed by the iterator    mylist.erase(it);      // printing all the elements of the list    cout << "List after deletion: ";    printList(mylist);}  // Driver codeint main(){    list<int> mylist;      // Get the list    for (int i = 1; i < 10; i++)        mylist.push_back(i * 10);      // Method 1 to get positionOfElementToBeDeleted    deleteByMethod1(mylist);      return 0;}Output:List originally:  10 20 30 40 50 60 70 80 90
List after deletion:  10 20 30 40 50 60 70 80

prev(listInt.end())
Below is the implementation of the above approach:
Program 1:
// C++ program to delete last element// of a List by passing its iterator  #include <iostream>#include <list>using namespace std;  // Function to print the listvoid printList(list<int> mylist){      // Get the iterator    list<int>::iterator it;      // printing all the elements of the list    for (it = mylist.begin(); it != mylist.end(); ++it)        cout << ' ' << *it;    cout << '\n';}  // Function to delete last element of list// using method 1void deleteByMethod1(list<int> mylist){      // printing all the elements of the list    cout << "\nList originally: ";    printList(mylist);      // Get the iterator    list<int>::iterator it;      // Get the positionOfElementToBeDeleted    // using method 1    it = prev(mylist.end());      // Erase the last element    // currently pointed by the iterator    mylist.erase(it);      // printing all the elements of the list    cout << "List after deletion: ";    printList(mylist);}  // Driver codeint main(){    list<int> mylist;      // Get the list    for (int i = 1; i < 10; i++)        mylist.push_back(i * 10);      // Method 1 to get positionOfElementToBeDeleted    deleteByMethod1(mylist);      return 0;}
List originally:  10 20 30 40 50 60 70 80 90
List after deletion:  10 20 30 40 50 60 70 80

Method 2:list::iterator it = listInt.end(); 
--it;
Below is the implementation of the above approach:Program 2:// C++ program to delete last element// of a List by passing its iterator  #include <iostream>#include <list>using namespace std;  // Function to print the listvoid printList(list<int> mylist){      // Get the iterator    list<int>::iterator it;      // printing all the elements of the list    for (it = mylist.begin(); it != mylist.end(); ++it)        cout << ' ' << *it;    cout << '\n';}  // Function to delete last element of list// using method 2void deleteByMethod2(list<int> mylist){      // printing all the elements of the list    cout << "\nList originally: ";    printList(mylist);      // Get the iterator    list<int>::iterator it;      // Get the positionOfElementToBeDeleted    // using method 2    it = --mylist.end();      // Erase the last element    // currently pointed by the iterator    mylist.erase(it);      // printing all the elements of the list    cout << "List after deletion: ";    printList(mylist);}  // Driver codeint main(){    list<int> mylist;      // Get the list    for (int i = 1; i < 10; i++)        mylist.push_back(i * 10);      // Method 2 to get positionOfElementToBeDeleted    deleteByMethod2(mylist);      return 0;}Output:List originally:  10 20 30 40 50 60 70 80 90
List after deletion:  10 20 30 40 50 60 70 80
My Personal Notes
arrow_drop_upSave
list::iterator it = listInt.end(); 
--it;

Below is the implementation of the above approach:
Program 2:
// C++ program to delete last element// of a List by passing its iterator  #include <iostream>#include <list>using namespace std;  // Function to print the listvoid printList(list<int> mylist){      // Get the iterator    list<int>::iterator it;      // printing all the elements of the list    for (it = mylist.begin(); it != mylist.end(); ++it)        cout << ' ' << *it;    cout << '\n';}  // Function to delete last element of list// using method 2void deleteByMethod2(list<int> mylist){      // printing all the elements of the list    cout << "\nList originally: ";    printList(mylist);      // Get the iterator    list<int>::iterator it;      // Get the positionOfElementToBeDeleted    // using method 2    it = --mylist.end();      // Erase the last element    // currently pointed by the iterator    mylist.erase(it);      // printing all the elements of the list    cout << "List after deletion: ";    printList(mylist);}  // Driver codeint main(){    list<int> mylist;      // Get the list    for (int i = 1; i < 10; i++)        mylist.push_back(i * 10);      // Method 2 to get positionOfElementToBeDeleted    deleteByMethod2(mylist);      return 0;}
List originally:  10 20 30 40 50 60 70 80 90
List after deletion:  10 20 30 40 50 60 70 80

cpp-list
STL
C++
STL
CPP
Writing code in comment?
Please use ide.geeksforgeeks.org,
generate link and share the link here.
Comments
Old Comments
Inheritance in C++
Map in C++ Standard Template Library (STL)
Multidimensional Arrays in C / C++
Socket Programming in C/C++
C++ Classes and Objects
Operator Overloading in C++
Bitwise Operators in C/C++
Constructors in C++
Virtual Function in C++
Copy Constructor in C++