Evaluate math expression

Question

Hi Guys,
I need to write java command line program to evaluate a mathematical
expression input by user without parantheses using Stack approach.
Can anyone give me the clue how to start of with.
Is it possible to evaluate the expression in infix notation directly using stack, without converting to prefix notation.
Thanks in advance

Answer 1

Is there something nicer?You can also use java 6 and javascripts. I saw a
thread where someone posted an example.
KajI posted something a couple of weeks back (reply #2):
http://forum.java.sun.com/thread.jspa?threadID=5137192
Of course, you don't need to bind any variables and can do it like this:import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
public class ScriptDemo {
    public static void main(String[] args) {
        ScriptEngineManager manager = new ScriptEngineManager();
        ScriptEngine engine = manager.getEngineByName("js");
        try {
            String expression = "3+4";
            Object result = engine.eval(expression);
            System.out.println(expression+" = "+result);
        } catch(ScriptException se) {
            se.printStackTrace();
    output: 3+4 = 7.0
*/