Hey guys:

I, being my curious self, am just wondering:
How is it that a C++ programm can interface with other programs? Is it possible?

I'll give an example: These dictionary password crackers. Correct me if I'm wrong, they are doing the equivalent of entering random words and letters into the password prompt.... except they type and hit the button a gazillion times.... correct? (I just gave it as an example)

I'm just interested in knowing what statements are used for that.
THanks

Edit*{More comfortable: Use the word "interact" instead of "interface". BTW: To all (and most) people who know more about programs than me, EMphaSIS on "Correct me if I'm wrong }