Stack: Basic program with all opertations


Stack program with basic operations

 
Java Code
import java.util.*;
    
class Stack{
        
    class Node{
        int data;
        Node next;
        Node(int data){
            this.data = data;
        }
    }

    Node top;
    

    public boolean isEmpty(){
        return top == null;
    }

    public void peek(){ 
        if(isEmpty()){
            System.out.println("Empty stack");
            return;
        }
            
        System.out.println("The top element of the stack is " + top.data);
    }

    public void pop(){
        if(isEmpty()){
            System.out.println("Empty stack");
            return;
        }
        int poppedItem = top.data;
        top = top.next;
        System.out.println("The popped item is "+poppedItem);
    }

    public void push(int data){
        Node node = new Node(data);
        node.next = top;
        top = node;
        System.out.println("The inserted item is " + data);

    }
    
    public void  printStack(){
        if(isEmpty()){
            System.out.println("Empty stack");
            return;
        }

        System.out.print("Stack elements are ");
        List allNodesList = new ArrayList<>();
        Node temp = this.top;
        while (temp != null) {
            allNodesList.add(Integer.toString(temp.data));
            temp = temp.next;
        }
        System.out.println(String.join(" -> ", allNodesList));
    }
    
    
    public static void main(String args[]){

        Stack stack = new Stack();
        stack.push(1);
        stack.push(2);
        stack.pop();
        stack.peek();
        stack.push(3);
        stack.push(4);
        stack.push(5);
        stack.printStack();
        stack.peek();
        stack.pop();
        stack.printStack();
        stack.pop();
        stack.printStack();
        
    }
        
}
Output

The inserted item is 1
The inserted item is 2
The popped item is 2
The top element of the stack is 1
The inserted item is 3
The inserted item is 4
The inserted item is 5
Stack elements are 5 -> 4 -> 3 -> 1
The top element of the stack is 5
The popped item is 5
Stack elements are 4 -> 3 -> 1
The popped item is 4
Stack elements are 3 -> 1



Thanks for feedback.



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