How to Clear All Elements from a List in C++?
In C++, std::list
is a container provided by the Standard Template Library (STL) that represents a doubly linked list and stores elements in non-contiguous memory locations. In this article, we will learn how to clear all elements from a list in C++.
Example:
Input: myList = {10, 20, 60, 80, 90}; Output: //After clearing, the list is empty myList = {};
Remove All Elements from a List in C++
To clear all elements from a std::list
in C++, we can use the std::list::clear()
function. This function removes all the elements from the list container, thus making the list empty and reducing its size to 0.
Syntax to Clear All Element From a List in C++
list_Name.clear();
C++ Program to Clear All Elements from a List
The below example demonstrates the use of the std::list::clear() function to clear all elements from a std::list in C++ STL.
// C++ program to demonstrate the use of the
// std::list::clear() function to clear all elements from a
// std::list
#include <iostream>
#include <list>
using namespace std;
int main()
{
// Creating a list
list<int> myList = { 10, 20, 60, 80, 90 };
// Printing the elements of the list
cout << "List Elements: ";
for (int ele : myList) {
cout << ele << " ";
}
cout << endl;
// Printing the size of the list before clearing it
cout << "Before clearing, the list has "
<< myList.size() << " elements" << endl;
// Clearing the list
myList.clear();
// Printing the size of the list after clearing it
cout << "After clearing, the list has " << myList.size()
<< " elements" << endl;
return 0;
}
Output
List Elements: 10 20 60 80 90 Before clearing, the list has 5 elements After clearing, the list has 0 elements
Time Complexity: O(N), where N is the number of elements in the list.
Auxiliary Space: O(1)
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