The Puzzle Answer and Which DB is this?

The answer is, yes it compiles. It's an interesting and certainly not intuitive gray area of C++. The int is declared outside of the braces following the if so is in scope for both those braces and those for the else branch.

Here's another question, not a puzzle though. Which major database is available in a free version on most platforms (Windows, Mac and Linux), in both 32 and 64 bit. It even comes with a free 246 page pdf e-book on getting started with it and no it's not from Microsoft or Sun. It's DB2 Express-C from IBM.

It's not open source but one sentence sums it up: Free to develop, deploy and distribute...no limits! Well technically the limit is 2GB of ram use compared to 4GB for the next version up that costs $2,995 a year. But unlike Microsoft SQL Server Express 2008, there's no 4GB database limit.

Relational databases are here mainly because of one man who worked for IBM. Edgar Frank Cobb, a British Computer Scientist. His 12 rules (there are 13 actually!) are an interesting read if you work with SQL.

DB2 works with C C++ and C# (and many other languages) and there's other free software that works with it such as the Eclipse based Data Studio that lets you debug SQL as well as the usual data management features. If you're interested in knowing more take a look at the DB2-Express Wiki and this free E-Book on developing for it:

If you want to know more about relational databases read

Link to "What is a Relational Database?" article