bind string to function

[hannes]

I'm making a program where the user can input a string and the result is shows.

For example: If the user inputs cos(0) then the output is 1

There are more functions then cos, in fact, there are a thousand more functions. Is there a way, instead of checking which function the user entered, that I can somehow bind the input to a real c++ function?

hannes

[hamsterman]

If all your functions are in form "name(argument)" it's simple. First parse the input to split it to the function name "cos" and the argument "0". Then convert the argument to a float.
Have an std::map<std::string, float(*function)(float)> with all the functions you need.

Where did you find 1000 functions?

[hannes]

Thanks for reply. Is there also a more C-like solution?

I had a look at maple, matlab,.. and I found some real nice functions to make myself.

[hamsterman]

The idea would be the same. Split input into function name and argument, find a function in a table, call it with the argument.

Note: if you want to compute "cos(0)+1" or "exp( sin(1) )", you'll have more work.

[hannes]

Ok. Computing "cos(0)+1" isn't a problem really. I have two algorithms to do that. I only had to know if there is a faster way to call functions.

hannes