How to realize the calculation of string Formula expression

[xjzh2005]

There are functions to implement in LABVIEW, but I didn't find such a function in cvi. 
I would like to ask you how to achieve it.

[RobertoBozzolo]

There is nothing like a formula parser and evaluator in CVI, the alternatives are to write your own code or to use an external library.

I have never had the need for such a library so I cannot give you a working solution. Nevertheless, a quick Google search resulted in this library that seems promising. I can imagine there are other possibly better alternatives out there.

Or, if you master the language, you could write a DLL in LabVIEW and call it in CVI.

[xjzh2005]

Thank you for your reply. I will try the method you suggested

[gdargaud]

I also wrote a solution in pure CVI code, which uses reverse notation and is simple to integrate to a program: https://www.gdargaud.net/Hack/SourceCode.html#PostfixEval

It does doubles and booleans.