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Session 1 — Microsoft Excel Programming — Why and How 7

Creating Instructions

Programming is really nothing more than creating instructions that tell the computer what
to do. In an office, for example, you might ask your assistant to make copies — that’s an
instruction. A computer program is the same — you tell the computer what to do. The
primary difference is that computers are really dumb and can’t figure out the fine points
on their own, so you must tell them exactly what to do in excruciating detail. Explicit
instructions are at the heart of any program.
Some instructions manipulate data. This can be as simple as adding two numbers, or as
complex as creating a chart. Other instructions control the execution of the program itself.
For example, a program could be designed to perform one task on weekdays and another
task on weekends. Still other instructions control how the program interacts with the user,
such as how it responds to the user’s selections from a menu or dialog box.

Handling Data
Every computer program works with data. This data can come in many forms — text,
numbers, and graphics — but for now you don’t need to be concerned with these details.
A fundamental part of programming consists of handling the data that the program uses.
You need a specific place to keep the data, and you also need to be able to get at the data
when necessary. From this perspective, data can be divided into two categories:

Data stored outside the program. For the most part, this category comprises data
that is stored in the cells of an Excel worksheet. Your program does not need to
create storage for such data, although the program can read and write it.
Data stored within the program. For data that is not stored elsewhere, a program
needs to create a storage location. A program uses variables to store internal data.
As you’ll see in later sessions, Excel programming offers a wide range of internal
data storage capabilities.
When you are programming with Excel, the data-handling capabilities available to you
are quite impressive. They provide a variety of data types that are specialized for storing
different kinds of data. You learn more about these data types in later sessions.

The VBA Language

You will use the VBA language to write Excel programs. VBA stands for Visual Basic for
Applications, and it is one of the two essential parts of Excel programming. The name Visual
Basic for Applications reflects the fact that VBA is based on Microsoft’s Visual Basic program-
ming language, and that it is designed for programming within applications — specifically,
the applications that comprise the Microsoft Office suite (Excel, Word, Access, PowerPoint,
and Outlook). VBA is relatively easy to learn, as programming languages go, but does not
sacrifice power and flexibility.
The task of programming in VBA is simplified by the VBA Editor, which is part of your
Excel installation. You can open the VBA Editor by pressing Alt+F11 when in Excel, or by