unable to correctly validate balanced parenthesis parsing in java method

Question

I have a method that\'s supposed to validate accurate opening and closing parenthesis in a string using java. This method will be used to parse mathematical expressions so it\'s

Answer 1

The immediate problem is this

String[] tokens = str.split("");

Gives you first char = "" if you use java 1.7 or less, so you will exit your loop since stack is empty...

Note: this has been changed in java 1.8 split difference between java 1.7 and 1.8

change to:

char[] tokens = str.toCharArray();

I guess however that you need to consider the fact that there can be chars before your first ( and that you may have other chars then ( and )