A: With experience one 
learns that some programming errors are very
elusive. I have many times seen users declaring that they have 
found
a bug in Turbo Pascal, but in the overwhelming majority of cases it
still is just a programming error, which just is more difficult to
find than the more clear-cut cases. When you have symptoms like 
your
program crashing from within the IDE, but working seemingly all
right when called as stand-alone, or something equally strange, 
you
might have one of the following problems.
- A variable or some variables in your code are uninitialized thus
  getting random values, which differ depending on your 
environment.
- Your indexes are overflowing. Set on the range check {$R+}
  directive for testing.
- An error in the pointer logic.
Normal debugging does not necessarily help in locating these 
errors
because one is easily led to debugging the wrong parts of one's
program. Especially the latter two reasons can cause errors which
seemingly have nothing to do with the actual cause. This results
from the fact that indexing and pointer errors can overwrite parts
of memory causing strange quirks in your program. If you have 
used
indexing with {$R-} or if you use pointer operations, sooner or
later you are bound to have these problems in developing your
applications.
   See Edward Mitchell (1993), Borland Pascal Developer's Guide,
275-288 for common programming errors and especially the 
information
on memory clobbering, in a useful chapter on debugging Turbo 
Pascal
programs. You might also take a look at your Turbo Pascal User's
Guide. At least version 7.0 has an instructive general
categorization of errors on pages 76-77.