Convert NSString of a math equation to a value

Question

I would like to know how to evaluate a string representation of an equation as if it were a real equation:

if(@\"15+14==23\")
{
    //True statement...
}
els         


        

Answer 1

So, this is a problem that I believe is a lot more complicated than the linked question lets on (although the question is asking for a "simple" equation parser).

Fortunately for you, I think this is a really interesting problem and have already written one for you: DDMathParser.

It has a good amount of documentation, including things like how to add it to your project and a high overview of its capabilities. It supports all of the standard mathematical operators, including logical and comparison operators (||, &&, ==, !=, <=, etc).

In your case, you'd do something like this:

NSNumber *result = [@"15+14 == 23" numberByEvaluatingString];
if ([result boolValue] == YES) {
  ....True statement....
} else {
  .....False statement.....
}

As a heads up, DDMathParser is made available under the MIT license, which requires you to include the copyright information and the full text of the license in anything that uses it.