This program take infix as an input, then convert into postfix and prefix. Please add a method to calculate the value of the INFIX expression in Java and at the end print output of infix, postfix prefix and the result. Thank you

import java.io.*;

class Node

{

public char data;

public Node lftChild;

public Node rhtChild;

public Node(char x)

{

data = x;

}

public void displayNode()

{

System.out.print(data);

}

}

class Stack

{

private Node[] a;

private int top, m;

public Stack(int max)

{

m = max;

a = new Node[m];

top = -1;

}

public void push(Node key)

{

a[++top] = key;

}

public Node pop()

{

return (a[top--]);

}

public boolean isEmpty()

{

return (top == -1);

}

}

class Stacktwo

{

private char[] a;

private int top, m;

public Stacktwo(int max)

{

m = max;

a = new char[m];

top = -1;

}

public void push(char key)

{

a[++top] = key;

}

public char pop()

{

return (a[top--]);

}

public boolean isEmpty()

{

return (top == -1);

}

}

class Conversion

{

private Stacktwo s;

private String input;

private String output = "";

public Conversion(String str)

{

input = str;

s = new Stacktwo(str.length());

}

public String inToPost()

{

for (int i = 0; i < input.length(); i++)

{

char ch = input.charAt(i);

switch (ch)

{

case '+':

case '-':

gotOperator(ch, 1);

break;

case '*':

case '/':

gotOperator(ch, 2);

break;

case '(':

s.push(ch);

break;

case ')':

gotParenthesis();

break;

default:

output = output + ch;

}

}

while (!s.isEmpty())

output = output + s.pop();

return output;

}

private void gotOperator(char opThis, int prec1)

{

while (!s.isEmpty())

{

char opTop = s.pop();

if (opTop == '(')

{

s.push(opTop);

break;

} else

{

int prec2;

if (opTop == '+' || opTop == '-')

prec2 = 1;

else

prec2 = 2;

if (prec2 < prec1)

{

s.push(opTop);

break;

} else

output = output + opTop;

}

}

s.push(opThis);

}

private void gotParenthesis()

{

while (!s.isEmpty())

{

char ch = s.pop();

if (ch == '(')

break;

else

output = output + ch;

}

}

}

class Tree

{

private Node root;

public Tree()

{

root = null;

}

public void insert(String s)

{

Conversion c = new Conversion(s);

s = c.inToPost();

Stack stack = new Stack(s.length());

s = s + "#";

int i = 0;

char symbol = s.charAt(i);

Node newNode;

while (symbol != '#')

{

if (symbol >= '0' && symbol <= '9' || symbol >= 'A'

&& symbol <= 'Z' || symbol >= 'a' && symbol <= 'z')

{

newNode = new Node(symbol);

stack.push(newNode);

} else if (symbol == '+' || symbol == '-' || symbol == '/'

|| symbol == '*')

{

Node ptr1 = stack.pop();

Node ptr2 = stack.pop();

newNode = new Node(symbol);

newNode.lftChild = ptr2;

newNode.rhtChild = ptr1;

stack.push(newNode);

}

symbol = s.charAt(++i);

}

root = stack.pop();

}

public void traverse(int type)

{

switch (type)

{

case 1:

System.out.print("Preorder Expression: ");

preOrder(root);

break;

case 2:

System.out.print("Inorder Expression: ");

inOrder(root);

break;

case 3:

System.out.print("Postorder Expression: ");

postOrder(root);

break;

default:

System.out.println("Invalid Choice");

}

}

private void preOrder(Node localRoot)

{

if (localRoot != null)

{

localRoot.displayNode();

preOrder(localRoot.lftChild);

preOrder(localRoot.rhtChild);

}

}

private void inOrder(Node localRoot)

{

if (localRoot != null)

{

inOrder(localRoot.lftChild);

localRoot.displayNode();

inOrder(localRoot.rhtChild);

}

}

private void postOrder(Node localRoot)

{

if (localRoot != null)

{

postOrder(localRoot.lftChild);

postOrder(localRoot.rhtChild);

localRoot.displayNode();

}

}

}