Stack in c++ header vs stack usinh linked list

Question

stack header is already available as below:

#include <stack>

int main()
{
stack<int> s;
s.push(1);
cout<< s.top();
}

why we are implementing again using linked list or array?

Answer 1

that is correct... does both give same optimisation? which should be used? it's mere for understanding purpose and one can directly go with stack header ?