List back() function in C++ STL

The C++ STL (Standard Template Library), the back() function is a member function of the std::list container. It is used to access the last element of a linked list (doubly linked list) container.

Here’s how you can use the back() function:

#include <iostream>
#include <list>

int main() {
    std::list<int> myList;

    // Adding elements to the list
    myList.push_back(1);
    myList.push_back(2);
    myList.push_back(3);

    // Accessing the last element using back()
    int lastElement = myList.back();

    std::cout << "Last element of the list: " << lastElement << std::endl;

    return 0;
}

In this example:

• We include the <list> header to use the std::list container.
• We create a std::list<int> called myList and add elements to it using the push_back() function.
• To access the last element of the list, we use the back() function, which returns a reference to the last element.
• Finally, we print the last element to the standard output.

Keep in mind that back() assumes that the list is not empty. If the list is empty and you attempt to call back(), it will result in undefined behavior. Therefore, it’s a good practice to check if the list is empty before using back(), especially in production code. You can use the empty() function to check if the list is empty.