How do I make a string math action into a real one?

I have this program that gets 2 numbers and an action ("+/*^-")..
I was wondering if there's a way to make that string into an action or do I have to make if's (or switch-case)?

If this is a school assignment then an if-else or switch should do it.
Realize though that the switch would need a char not an int.

Otherwise you can have a look at the JavaScript engine shipped with Java 6.

You may want to push and pop operands off a stack if you want to have order of operations ie

Code:

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2 + 3 * 6 != ( 2 + 3 ) * 6

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