What does this code output?

I can't seems to get the output of this code to display in the console window, evening after implementing a System.out.println() for each variable. Could someone give me some suggestion or possible output for the code, thanks.

Code java:

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 public class Evaluate
{
public static void main(String[] args)
{
Stack<String> ops = new Stack<String>();
Stack<Double> vals = new Stack<Double>();
while (!StdIn.isEmpty())
{ // Read token, push if operator.
String s = StdIn.readString();
if (s.equals("(")) ;
else if (s.equals("+")) ops.push(s);
else if (s.equals("-")) ops.push(s);
else if (s.equals("*")) ops.push(s);
else if (s.equals("/")) ops.push(s);
else if (s.equals("sqrt")) ops.push(s);
else if (s.equals(")"))
{ // Pop, evaluate, and push result if token is ")".
String op = ops.pop();
double v = vals.pop();
if (op.equals("+")) v = vals.pop() + v;
else if (op.equals("-")) v = vals.pop() - v;
else if (op.equals("*")) v = vals.pop() * v;
else if (op.equals("/")) v = vals.pop() / v;
else if (op.equals("sqrt")) v = Math.sqrt(v);
vals.push(v);
} // Token not operator or paren: push double value.
else vals.push(Double.parseDouble(s));
}
StdOut.println(vals.pop());
}
}

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These forums don't work like that. Perhaps you should be getting to the root of the problem - like why you see no output (does it compile?) - rather than asking someone to do your work for you

Step 1: Format your code to be easily readable (i.e. add tabs).

Step 2: What issue are you running into specifically? Compiler errors? Runtime errors? Which ones?

fyi, StdOut and StdIn are not defined by default in Java, use System.out and System.in instead.

Quote:

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Originally Posted by copeg

These forums don't work like that. Perhaps you should be getting to the root of the problem - like why you see no output (does it compile?) - rather than asking someone to do your work for you

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That what I really meant to ask? I tried compiling this program several times but did't see any output. So, copeg or anyone could you give me any suggestion on why I'm not seeing any output when I run this code. Hey, I any revise it a little to showing that I am really putting effort into this. Here is the revise version:

Code java:

---

import java.io.BufferedInputStream;
import java.lang.*;
import java.util.*;
import java.util.Scanner;
import java.io.PrintWriter;
import java.io.UnsupportedEncodingException;
import java.util.Locale;
 
 
public class StdIn {
 
	 private static Scanner scanner = new Scanner(new BufferedInputStream(System.in));
 
 
	 public static boolean isEmpty() {
	        return !scanner.hasNext();
	    }
 
	 public static String readString() {
	        return scanner.next();
	    }
 
 
 
	public  static void main (String args[]){ 
 
 
		//InputStreamReader input = new InputStreamReader(System.in);
		//BufferedReader reader = new BufferedReader(input);
 
		Stack<String> ops = new Stack<String>();
 
		Stack<Double> vals = new Stack<Double>();
		//String s = reader.readLine();
 
 
 
		while (!StdIn.isEmpty())
		{ // Read token, push if operator.
			String s = StdIn.readString();
		if (s.equals("(")) ;
		else if (s.equals("+")) ops.push(s);
		else if (s.equals("-")) ops.push(s);
		else if (s.equals("*")) ops.push(s);
		else if (s.equals("/")) ops.push(s);
		else if (s.equals("sqrt")) ops.push(s);
		else if (s.equals(")"))
 
		{ // Pop, evaluate, and push result if token is ")".
		String op = ops.pop();
		double v = vals.pop();
		if (op.equals("+")) v = vals.pop() + v;
		else if (op.equals("-")) v = vals.pop() - v;
		else if (op.equals("*")) v = vals.pop() * v;
		else if (op.equals("/")) v = vals.pop() / v;
		else if (op.equals("sqrt")) v = Math.sqrt(v);
		vals.push(v);
		System.out.println(vals.push(v));
		} // Token not operator or paren: push double value.
		else vals.push(Double.parseDouble(s));
		System.out.println(Double.parseDouble(s));
 
		}
		System.out.println(vals.pop());	
 
 
 
	}
 
 
 
 
 
	}

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The current issue I am having with this code is: figuring out why don't I see any output. I take some of your suggestion: Here is a revise version of my code:

Code java:

---

          //import java.io.*;
	//import java.math.*;
	//import java.io.OutputStreamWriter;
	import java.io.BufferedInputStream;
	//import java.lang.*;
	import java.util.*;
	import java.util.Scanner;
	//import java.io.PrintWriter;
	//import java.io.UnsupportedEncodingException;
	//import java.util.Locale;
 
 
	public class StdIn {
 
	private static Scanner scanner = new Scanner(new BufferedInputStream(System.in));
 
 
	 public static boolean isEmpty() 
		 { return !scanner.hasNext();}
 
 
	 public static String readString() 
		 { return scanner.next();}
 
 
 
	public  static void main (String args[]){ 
 
 
	Stack<String> ops = new Stack<String>();
 
	Stack<Double> vals = new Stack<Double>();
 
 
 
	while (!StdIn.isEmpty())
	{ // Read token, push if operator.
		String s = StdIn.readString();
	if (s.equals("(")) ;
	else if (s.equals("+")) ops.push(s);
	else if (s.equals("-")) ops.push(s);
	else if (s.equals("*")) ops.push(s);
	else if (s.equals("/")) ops.push(s);
	else if (s.equals("sqrt")) ops.push(s);
	else if (s.equals(")"))
 
	{ // Pop, evaluate, and push result if token is ")".
	String op = ops.pop();
	double v = vals.pop();
	if (op.equals("+")) v = vals.pop() + v;
	else if (op.equals("-")) v = vals.pop() - v;
	else if (op.equals("*")) v = vals.pop() * v;
	else if (op.equals("/")) v = vals.pop() / v;
	else if (op.equals("sqrt")) v = Math.sqrt(v);
	vals.push(v);
	System.out.println(vals.push(v));
	} // Token not operator or paren: push double value.
	else vals.push(Double.parseDouble(s));
	System.out.println(Double.parseDouble(s));
 
	}
	System.out.println(vals.pop());	
 
 
	}
 
 
	}

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