Converting a string into a line of code.

[Fatboy]

If I have a CString str; and say I have a function double y(double x). Suppose the string in str is "x*cos(x)", and I want the function double y(double x) to return what is written in str, is this at all feasible using MFC or any other standard utility libraries?

[John E]

You mean that you want 'y' to return a string instead of a double?

[jim enright]

if i read you right you can simply let the y fn return a double and then convert the double into a CString:

z = y(x);

CSting str_of_z;

str_of_z.Format("%10.6f",z);

[Hobson]

If I have a CString str; and say I have a function double y(double x). Suppose the string in str is "x*cos(x)", and I want the function double y(double x) to return what is written in str, is this at all feasible using MFC or any other standard utility libraries?

There is no standard tools for evaluating arithmetic expressions. Searching web, you can find some handy tools, examples, etc. Try googling for something like 'arithmetic expression parser' or something similar. However, thing I would recommend, is LUA interpreter. It is very handy, lightweight tool which may be used for parsing expressions. You might consider it too big to just parse expressions, but I think that its advantages are worth it: It supports variables, built-in basic math functions, custom functions, is portable (I compiled and used it on Windows and two Linux distros).
I tried also boost spirit library, but it is totally illegible for me

Cheers,
Hob

[EmbeddedC]

Hahaha,

That's funny, only Hobson understood Fatboy's question.
Fatboy would like to create an application something similar like Matlab (but I guess a very small one).
Peace!

[Fatboy]

Yes, a very very small Matlab, or you can view it as a something more than a graphic calculator. Thanks guys for your help, and respect to Hobson for understanding my question, I know it was hard to decipher!