best way to parsing this line

[wysota]

Let me put it this way - the parser is something that deals with grammar (syntax), not logic (semantics). I suggest you parse your file into some kind of list or tree or whatever else you want and then perform semantic checks or actions on the resulting structure. Of course you can combine the two operations to save time when you can deduce while parsing that the result will be useless (like when the number of items in each line differs). If you wrap that all in a class with different methods performing different tasks, the code should be simple and easily readable.

[mickey]

OK, I could put it in a vector <vector<double> > as you can see before and then check everything (eg. find the number of line, the number of element of a line, the min max values of each single line). All those need to scan the vector of vector from begin to end; so I thought to do this while parsing (but It'll soil the parser). So, read what you have write above, I'm thinking to do one method that while parsing do: push_back into the vector, increment the number of elements, and check for min, max. Are you mean this? With this parser appear more light...thanks

[wysota]

There is no single correct way to complete the task. You may do as you see fit depending on what's most important for you.

[mickey]

Yes, but I'm looking for the most elegant......

[wysota]

In what terms? According to me the most elegant way is to do it in two passes - one constructs the syntax tree and the other validates and operates on it.

[ComaWhite]

boost spirit is a good parser to use.i've used it for a simple scripting language.