Teach Yourself Borland C++ in 14 Days - portal

408 Day 11
NOTE
The code in this example gets the values for the Width and Height
properties of the form, performs some calculations, and then sets Width
and Height back to where they were when you started. In the end
nothing changes, but there is a good reason for assigning values to the
Width and Height properties at the end of the function.
If you don’t actually do something with the variables x and y, you
wouldn’t be able to inspect them because the compiler will optimize
them and they won’t be available to watch. Essentially, the compiler
can look ahead, see that the variables are never used, and just more or
less discard them. Putting the variables to use at the end of the function
avoids having them optimized away by the compiler.
I’ve brought this up several times now, but I want to make sure you
have a basic understanding of how an optimizing compiler works.
When you start debugging your applications, this knowledge will help
avoid some frustration when you start getting those Variable ‘x’ has
been optimized and is not available messages in the Watch List.
The Debug Inspector
NOTE
Simply stated, the Debug Inspector allows you to view data objects such as classes and
components (components are really just classes, anyway). You can also inspect simple data
types such as integers, character arrays, and so on, but those are best viewed with the Watch
List. The Debug Inspector is most useful in examining classes and structures.
You can use the Debug Inspector only when program execution is
paused under the debugger.
To inspect an object, click on the object’s name in a source file and choose Inspect from the
Code Editor speed menu (or press Alt+F5). You could also choose Run | Inspect from the
main menu.