In Java please, and please print output to make sure it is correct Complete the

Question

In Java please, and please print output to make sure it is correct

Complete the following method buildExprTree(String postfix) that takes a postfix expression as input and builds the corresponding expression tree. For instance if the given postfix expression is "3 5 + 4/", the expression tree is as in below image. Assume all arithmetic operations are binary. You may further assume that the input postfix expression will always be a valid postfix expression, in other words, you do not have to consider error cases. (You may assume that you have access to a Stack class.) void buildExprTree(String postfix) { StringTokenizer tokens = new StringTokenizer(postfix); while (tokens.hasMoreTokens()) { String nextToken = tokens.nextToken();

Explanation / Answer

// I have wrote thr code for the function, but since you have not given the sample input/output, I con't know how the flow should be

import java.util.Stack;
import java.util.StringTokenizer;

public class Test{
   class Node{
       String data;
       Node left, right;
       public Node(String d, Node l, Node r){
           data = d;
           left = l;
           right = r;
       }
   }
   void buildExprTree(String postfix){
       Stack<Node> s = new Stack<Node>();
       StringTokenizer tokens = new StringTokenizer(postfix);
       while(tokens.hasMoreTokens()){
           String nextToken = tokens.nextToken();
           if(nextToken.equals("+") || nextToken.equals("-") || nextToken.equals("*") || nextToken.equals("/")){
               Node op1 = s.pop();
               Node op2 = s.pop();
               Node temp = new Node(nextToken, op1, op2);
               s.push(temp);
           }
           else{
               s.push(new Node(nextToken, null, null));
           }
       }
   }
}

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