public class Node {
    Object data;
    Node next;
    public Node(){
            }
    public Node(Object info,Node n){
        this.data=info;
        this.next=n;
    }
    public Object getData(){
        return this.data;
    }
    public void setData(Object data){
        this.data=data;
    }
    
    public Node getNext(){
        return this.next;
    }
    
    public void setNext(Node next){
        this.next = next;
    }
}

public class Stack{
    private static  Node topNode;
    private static int size;
    
    public static boolean isEmpty(){
        return (topNode==null);
    }
    public static int size(){
    return size;
}

    public static void push(Object ch){
        Node newNode = new Node(ch,null);
        if(isEmpty())
                topNode = newNode;
        else{
                newNode.setNext(topNode);
                topNode = newNode;
        }            
    }

    public Object pop(){
        Object temp=' ';
        if(!isEmpty()){
        temp = topNode.getData();
        topNode = topNode.getNext();
        }
        return temp;
    }
    public Object top(){
    if(isEmpty())
        System.out.println("Empty stack");
        return topNode.getData();
        
}
public int prec(Object n)
{
    if(n.equals('+')||n.equals('-'))
        return 1;
    else if(n.equals('*')||n.equals('/'))
        return 2;
    else if(n.equals('^'))
            return 3;
    else
        return 0;
}

public String postfix(String s)
{
    String output="";
    Stack S=new Stack();
    for(int i=0;i<s.length();i++)
    {
        char c=s.charAt(i);
        
        if(c==('+')||c==('-')||c==('*')||c==('/')||c==('^'))
            {
                while(!S.isEmpty() &&prec(S.top())>= prec(c))
                output+=S.pop();
            S.push(c);
            }
        else if(c=='(')
        {
            S.push(c);
        }
        else if(c==')')
        {
            while(!S.top().equals('('))
                    output+=S.pop();
            S.pop();
        }
        else
            output+=c;
    }
    while(!S.isEmpty())
        output+=S.pop();
    return output;
}
public String Evaluation(String x)
{
    
    Stack S=new Stack();
    for(int i=0;i<x.length();i++)
    {
        char c=x.charAt(i);
        String s="0"+c;
        
        if(c=='+')
        {
            int z=Integer.parseInt((String)S.pop())+Integer.parseInt((String)S.pop());
            S.push(Integer.toString(z));
        }
        else if(c=='*')
        {
            int z=Integer.parseInt((String)S.pop())*Integer.parseInt((String)S.pop());
            S.push(Integer.toString(z));
            
        }
        else if(c=='/')
        {    int u=Integer.parseInt((String)S.pop());
            
            int z=Integer.parseInt((String)S.pop())/u;
            S.push(Integer.toString(z));
            
        }
        else if(c=='-')
        {    int u=Integer.parseInt((String)S.pop());
            int z=Integer.parseInt((String)S.pop())-u;
           S.push(Integer.toString(z));
                      
        }
        else if(c=='^')
        {    int u=Integer.parseInt((String)S.pop());
            int z=Integer.parseInt((String)S.pop());
            int m=((int)Math.pow(z,u));
            S.push(Integer.toString(m));
        }
        else
        S.push(s);
    }
    
   return (String)S.pop();
}
}

import javax.swing.*;
public class Test{
public static void main(String[] args) {
     Stack s=new Stack();
    String input=JOptionPane.showInputDialog("Enter Expression");
     String output="";
    String m=s.postfix(input);
    System.out.println("Postfix is "+m);
   String n=s.Evaluation(m);
      System.out.println("Result ="+n);

  }

  }