C++ List Library - clear() Function

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Description

The C++ function std::list::clear() destroys the list by removing all elements from the list and sets size of list to zero.

Declaration

Following is the declaration for std::list::clear() function form std::list header.

C++98

void clear();

C++11

void clear() noexcept;

Parameters

None

Return value

None

Exceptions

This member function never throws exception.

Time complexity

Linear i.e. O(n)

Example

The following example shows the usage of std::list::clear() function.

#include <iostream>
#include <list>

using namespace std;

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

   cout << "Initial size of list = " << l.size() << endl;

   l.clear();

   cout << "Size of list after clear operation = " << l.size() << endl;

   return 0;
}

Let us compile and run the above program, this will produce the following result −

Initial size of list = 5
Size of list after clear operation = 0