Please change this method to recursive method. public String postfix() { final ExpressionNodes nodes = new ExpressionNodes(); for (String element : expression.split(\" \")) { if (isOperator(element)) { String rightNode = nodes.pop(); String leftNode = nodes.pop(); nodes.push((leftNode + \" \" + rightNode + \" \" + element)); } else { nodes.push((element)); } } return nodes.pop(); } Solution public class Main{ public String postfix(int count) final ExpressiononNodes nodes = new ExpressiononNodes (); for( String element : expression split(\" \")) { if (Is Operator(int element)) { String rightNode = nodes.pop(); String leftNode = nodes.pop(); nodes.push((leftNode + \" \" + rightNode + \" \" +element)); } else { nodes.push ((element)); }} if (count <=0) { return nodes.pop(); } else { postfix(count - 1); }} Public static void Main(String[] args) { Main n = new Main(); n.postfix(element); }.

1. Please change this method to recursive method.
public String postfix() {
final ExpressionNodes nodes = new ExpressionNodes();
for (String element : expression.split(" ")) {
if (isOperator(element)) {
String rightNode = nodes.pop();
String leftNode = nodes.pop();
nodes.push((leftNode + " " + rightNode + " " + element));
} else {
nodes.push((element));
}
}
return nodes.pop();
}
Solution
public class Main{
public String postfix(int count)
final ExpressiononNodes nodes = new ExpressiononNodes ();
for( String element : expression split(" "))
{
if (Is Operator(int element))
{
String rightNode = nodes.pop();
String leftNode = nodes.pop();
nodes.push((leftNode + " " + rightNode + " " +element));
}
else
{
nodes.push ((element));
}}
if (count <=0)
{
return nodes.pop();

2. }
else
{
postfix(count - 1);
}}
Public static void Main(String[] args)
{
Main n = new Main();
n.postfix(element);
}