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How to Clear a Stack in C++?

Last Updated : 23 Jul, 2025

In C++, clearing a stack means removing all element from the stack container leaving it empty. In this article, we will learn how to clear a stack in C++.

The most efficient method to clear a stack is by assigning the new empty stack to our original stack container. Let's take a look at the code example:

#include <bits/stdc++.h>
using namespace std;

int main() {
    stack<int> s;
    s.push(1);
    s.push(5);
    s.push(4);
  	
  	// Initial size of the stack
  	cout << s.size() << endl;

    // Assigning the new empty stack 
    s = stack<int>();
  
  	// Final size of the stack
  	cout << s.size() << endl;

    return 0;
}

This method destroys the previously stored elements.

There are also a few other methods to clear a stack in C++. They are given below:

A new empty stack container is swapped with original std::stack container by using stack swap() function. This method is similar to the previous method but allows us to save the stack elements before clearing it.

#include <bits/stdc++.h>
using namespace std;

int main() {
    stack<int> s;
    s.push(1);
    s.push(5);
    s.push(4);
  
  	// Initial size of the stack
  	cout << s.size() << endl;

    // Swap the stack with new empty stack
  	stack<int> s1;
    s.swap(s1);

    // Final size of the stack
  	cout << s.size() << endl;
  
    return 0;
}

The stack pop() method removes the top element of the stack. It can be used to clear the stack by popping all the elements one by one in a loop until the stack is empty.

#include <bits/stdc++.h>
using namespace std;

int main() {
    stack<int> s;
    s.push(1);
    s.push(5);
    s.push(4);
  
  	// Initial size of the stack
  	cout << s.size() << endl;

    // Removing all elements from stack one by one
    while (!s.empty())
        s.pop();

    // Final size of the stack
  	cout << s.size() << endl;

    return 0;
}

Explanation: In the above code, we remove all elements from stack container one by one till stack empty() does not returns true.

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