How do I convert String to an executable statement 1

[gismo]

I'm passing an mathematical equation as a string from visual basic to a C function the contents of the LPCSTR would look like

SI0=(SI1 + SI2) * SI3 / SI4;
Where SI1,SI2,SI3, and SI4 are variables that exist in the function. How do I convert the string into an executable line of code.

 

[xwb]

1) Parse the expression and convert it to reverse polish notation (RPN)
2) Execute the expression in reverse polish

The simplest method of parsing is recursive descent. Work out the grammar of your expression and write the rules (in BNF). Then write one routine for every rule.

As you are parsing, you can convert the expression into RPN. eg

SI0=(SI1 + SI2) * SI3 / SI4

becomes

SI1 SI2 + SI3 * SI4 / SI0 =

 

[gismo]

Thanks xwb for your suggestion. I was hoping it would be simpler than that After reading your response I searched the web again based on the information you gave me and found some code at

http://www.parsifalsoft.com/examples/evalexpression/

that will do it for me.Thanks again for your time.