This is a C project in which the user enters a numerical expression. Most of the numerical expressions will contain some or all of these characters: '( )', '[ ]', '{ }'. Sadly, there are a lot of times where someone types the expression but forgets to open/close a bracket or closes the brackets in a wrong order, making the expression invalid. The purpose of this program is to check if the numerical expression is valid (if all the brackets have been opend and closed correctly).
