programming-for-dummies

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Making User Interfaces with Event-Driven Programming
Making User Interfaces with
Event-Driven Programming
In the early days, using a program was fairly simple. After typing the command
to run a particular program, that program might ask a question such as
What is your name?
At this point, you had no choice but to type a name, such as Joe Smith. After
you typed in your name, the program might respond with
Hello, Joe Smith. What month were you born?
The moment you typed in a month, such as April, the program might
respond:
What day were you born?
And so on. If you wanted to type your day of birth before your month of
birth, you couldn’t because the program controlled your options.
Not surprisingly, using a computer like this was frustrating to most people,
so computer scientists soon invented something called a graphical user interface
(abbreviated as GUI).
A GUI displays multiple options to the user in the form of pull-down menus,
windows, buttons, and check boxes. Suddenly, instead of the computer dictating
what the user could do at any given time, the user could tell the computer
what to do at any given time, just by choosing one of many available
commands.
Forcing each program to display menus and windows had two advantages
for users:
✦ It made using a computer much easier. Instead of having to type in
commands, users could just click the command they wanted to use.
✦ It’s fairly easy to figure out how to use different types of programs.
After you understand that you can choose the Print command in the File
menu, you know how to print in any program whether it’s a word processor,
a database, or an image editing program.