Just a warning:
This is bullshit, learning C++ in 21 days or 365 for that matter is bullshit, just because they renamed the book doesn't mean that's any better
Stay away from everything that promises you to teach you C++ in a matter of days, really learning C++ takes years to come by
Feel free to read though, but never pay a cent for books like this
You're better off with books like: "Ivor Horton's beginning ANSI C++"
Notice the 'beginning' part in the title, the book has 1000+ pages...
I hope that gives you the idea of how stupid: "teaching yourself C++ in 21 days sounds"
-SCHiM