Data Structure - Stack (Concept and STL, C++ code)

Stack

Last In First Out
Stack is a linear data structure which follows a LIFO order
stack is implemented with array or linked list

• push() : Push data into the stack
• pop() : Removes the most recently added element from the stack

Stack’s advantage and disadvantage

Assuming that the stack is implemented with array

1. Advantage of Stack
   • Simple structure, easy to implement
   • Fast data storage and reading

1. Disadvantage of stack
   • The maximum number of data should be determined in advance.
   • Storage space may be wasted (if the maximum number is fixed but not all of the space is used)

Common point - Stack and Queue

Structure that has restriction to access to the data
Structure that can only insert or subtract data at one end

stack - C++ Container library

c++ stack.

#include <iostream>
#include <stack>
using namespace std;

int main()
{
    stack<int> s1; 
	
    s1.push(10);
    s1.push(20);
    s1.push(30);
    
    cout << s1.top() << endl; //30
    
    s1.pop();
    
    cout << s1.top() << endl; //20
    
}

#include <iostream>
#include <stack>

using namespace std;

int main()
{
	stack <int> s;
	s.push(1);
	s.push(2);
	s.push(3);
	
	s.pop();
	s.push(4);
	s.pop();
	while(!s.empty())
	{
		cout << s.top() << " ";
		s.pop();
	}
	
	//2 1
	return 0;
}

Usage or Stack

• How the function works in the process
  • stack is used when a function calls works
• The stack structure is the basis of the process execution