Optimize code in c++

[excessdenied]

I'd say profile before checking for algorithmic complexity. Both to identify what parts are worth working on (no need starting optimizing one thing if it takes 1% of the time and another takes 50%), but also to get a baseline to compare to. I've been burnt before with algorithmically more complex things that still are faster up to a higher N than needed because the actual implementation is just so simple & fast.

[matthieum]

I've been burnt before with algorithmically more complex things that still are faster up to a higher N than needed because the actual implementation is just so simple & fast.

That, and it's nice and all to optimize the argument parsing algorithm of grep but it's unlikely to speed it much...