Stack Class in Java

// Java Program Implementing Stack Class
import java.util.Stack;

public class StackExample 
{
    public static void main(String[] args) 
    {
        // Create a new stack
        Stack<Integer> s = new Stack<>();

        // Push elements onto the stack
        s.push(1);
        s.push(2);
        s.push(3);
        s.push(4);

        // Pop elements from the stack
        while(!s.isEmpty()) {
            System.out.println(s.pop());
        }
    }
}

// Java code for stack implementation
import java.util.Stack;

class Main
{   
    // Pushing element on the top of the stack
    static void stack_push(Stack<Integer> stack)
    {
        for(int i = 0; i < 5; i++)
        {
            stack.push(i);
        }
    }
    
    // Popping element from the top of the stack
    static void stack_pop(Stack<Integer> stack)
    {
        System.out.println("Pop Operation:");

        for(int i = 0; i < 5; i++)
        {
            Integer y = (Integer) stack.pop();
            System.out.println(y);
        }
    }

    // Displaying element on the top of the stack
    static void stack_peek(Stack<Integer> stack)
    {
        Integer element = (Integer) stack.peek();
        System.out.println("Element on stack top: " + element);
    }
    
    // Searching element in the stack
    static void stack_search(Stack<Integer> stack, int element)
    {
        Integer pos = (Integer) stack.search(element);

        if(pos == -1)
            System.out.println("Element not found");
        else
            System.out.println("Element is found at position: " + pos);
    }


    public static void main (String[] args)
    {
        Stack<Integer> stack = new Stack<Integer>();

        stack_push(stack);
        stack_pop(stack);
        stack_push(stack);
        stack_peek(stack);
        stack_search(stack, 2);
        stack_search(stack, 6);
    }
}

// Java program to add the
// elements in the stack
import java.io.*;
import java.util.*;

class StackDemo {
  
      // Main Method
    public static void main(String[] args)
    {

        // Default initialization of Stack
        Stack stack1 = new Stack();

        // Initialization of Stack
        // using Generics
        Stack<String> stack2 = new Stack<String>();

        // pushing the elements
        stack1.push("4");
        stack1.push("All");
        stack1.push("Geeks");

        stack2.push("Geeks");
        stack2.push("For");
        stack2.push("Geeks");

          // Printing the Stack Elements
        System.out.println(stack1);
        System.out.println(stack2);
    }
}

// Java program to demonstrate the accessing
// of the elements from the stack
import java.util.*;
import java.io.*;

public class StackDemo {

      // Main Method
    public static void main(String args[])
    {
        // Creating an empty Stack
        Stack<String> stack = new Stack<String>();

        // Use push() to add elements into the Stack
        stack.push("Welcome");
        stack.push("To");
        stack.push("Geeks");
        stack.push("For");
        stack.push("Geeks");

        // Displaying the Stack
        System.out.println("Initial Stack: " + stack);

        // Fetching the element at the head of the Stack
        System.out.println("The element at the top of the"
                           + " stack is: " + stack.peek());

        // Displaying the Stack after the Operation
        System.out.println("Final Stack: " + stack);
    }
}

// Java program to demonstrate the removing
// of the elements from the stack
import java.util.*;
import java.io.*;

public class StackDemo {
    public static void main(String args[])
    {
        // Creating an empty Stack
        Stack<Integer> stack = new Stack<Integer>();

        // Use add() method to add elements
        stack.push(10);
        stack.push(15);
        stack.push(30);
        stack.push(20);
        stack.push(5);

        // Displaying the Stack
        System.out.println("Initial Stack: " + stack);

        // Removing elements using pop() method
        System.out.println("Popped element: "
                           + stack.pop());
        System.out.println("Popped element: "
                           + stack.pop());

        // Displaying the Stack after pop operation
        System.out.println("Stack after pop operation "
                           + stack);
      
       System.out.println("Is stack empty? " + stack.empty()); // Should print false
       // Pop remaining elements
        stack.pop();
        stack.pop();
        stack.pop();

        // Check if the stack is empty
        System.out.println("Is stack empty? " + stack.empty()); // Should print true
    }
}

// A Java Program to show implementation
// of Stack using ArrayDeque

import java.util.*;

class GFG {
    public static void main (String[] args) {
        Deque<Character> stack = new ArrayDeque<Character>();
        stack.push('A');
        stack.push('B');
        System.out.println(stack.peek());
        System.out.println(stack.pop());
    }
}

import java.util.*;
import java.util.stream.Collectors;

class GFG {
    public static void main (String[] args) {
 
          Stack<Integer> stack = new Stack<>();
        Deque<Integer> deque = new ArrayDeque<>();

        stack.push(1);//1 is the top
        deque.push(1);//1 is the top
        stack.push(2);//2 is the top
        deque.push(2);//2 is the top

        List<Integer> list1 = stack.stream().collect(Collectors.toList());//[1,2]
          System.out.println("Using Stack -");
          for(int i = 0; i < list1.size(); i++){
              System.out.print(list1.get(i) + " " );
        }
          System.out.println();

        List<Integer> list2 = deque.stream().collect(Collectors.toList());//[2,1]
          System.out.println("Using Deque -");
          for(int i = 0; i < list2.size(); i++){
              System.out.print(list2.get(i) + " " );
        }
          System.out.println();
      
    }
}