C++ Stack Library - size() Function

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Description

The C++ function std::stack::size() returns the total number of element present in the stack.

Declaration

Following is the declaration for std::stack::size() function form std::stack header.

C++98

size_type size() const;

Parameters

None

Return value

Returns the number of element present in the stack.

Exceptions

Depends upon underlying container.

Time complexity

Constant i.e. O(1)

Example

The following example shows the usage of std::stack::size() function.

#include <iostream>
#include <stack>

using namespace std;

int main(void) {
   stack<int> s;

   cout << "Initial size of stack = " << s.size() << endl;

   for (int i = 0; i < 5; ++i)
      s.push(i + 1);

   cout << "Stack size after push operation = " << s.size() << endl;

   return 0;
}

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

Initial size of stack = 0
Stack size after push operation = 5