couple of options :
1. have a if cascade on the input string to call the appropriate function
(pseudo-code)
if ( s == "foo" )
foo();
else if ( s == "bar" )
bar();
else
cout<< "unsupported function";
2. have an map of function pointers (?) keyed to the "string" and call the appropriate function. (I'm no export on function pointers, so no pseudo-code )
I'm certain there are other ways to do it.
Good luck.
Max.