How to use strcat in c?

Dear condzero,
Hi,
Thanks for your help and reply.
But there is still a problem for me that I couldn't manage it.
Would you please let me know how to OPEN A FILE FOR LOGGING OUTPUT IN ANALYZE MODE?
Which function(s) do you use to OPEN A FILE FOR LOGGING OUTPUT IN ANALYZE MODE?
That would be great if you can discuss the case a bit.
I look forward to hearing from you.

Also thank anybody else who has spend time to answer to this topic to bring some help to the point.

Regards,
Zest.