How to parse and solve equation string in Java?

Question

I have a string like 3x^2+5X+7 and what I want to do is, get x value from the user and make the program solve this equation. I couldn't figure it out how I am gonna do this so far. I would be really glad if you help me.

Create a stack of characters, Put all Chars to that stack now you need to get the priority of each traversing on the stack — Basil Battikhi, Nov 14 '19 at 15:00
Add code snippet to here for discussing your approach and let us see what is wrong on your code then you can request help for non-working states or lines. — oguzhan00, Nov 14 '19 at 15:02
Please see: [Why is “Can someone help me?” not an actual question?](http://meta.stackoverflow.com/q/284236) — EJoshuaS - Stand with Ukraine, Nov 14 '19 at 15:14

score 4 · Answer 1 · answered Nov 14 '19 at 15:10

You could try this:

ScriptEngineManager mgr = new ScriptEngineManager();
ScriptEngine engine = mgr.getEngineByName("JavaScript");
int x = 42;
String foo = "3*x^2+5*x+7";
String input = foo.replaceAll("x", x);
System.out.println(engine.eval(foo));

(How to evaluate a math expression given in string form?)

How to parse and solve equation string in Java?

1 Answers1