list::clear() in C++ STL

Lists are containers used in C++ to store data in a non contiguous fashion, Normally, Arrays and Vectors are contiguous in nature, therefore the insertion and deletion operations are costlier as compared to the insertion and deletion option in Lists.

list::clear()

clear() function is used to remove all the elements of the list container, thus making it size 0.

Syntax :

listname.clear()
Parameters :
No parameters are passed.
Result :
All the elements of the list are
removed ( or destroyed )

Examples:

Input  : list{1, 2, 3, 4, 5};
         list.clear();
Output : list{}

Input  : list{};
         list.clear();
Output : list{}

Errors and Exceptions

1. It has a no exception throw guarantee.

2. Shows error when a parameter is passed. 

CPP

// CPP program to illustrate
// Implementation of clear() function
#include <iostream>
#include <list>
using namespace std;

int main()
{
 list<int> mylist{ 1, 2, 3, 4, 5 };

 mylist.clear();
 // List becomes empty

 // Printing the list
 for (auto it = mylist.begin(); it != mylist.end(); ++it)
  cout << ' ' << *it;
 return 0;
}

Output:

No Output

Time Complexity: O(n)
Auxiliary Space: O(1)