programming-for-dummies

300
Elements of a User Interface
Showing information back to the user
User interfaces can show information to the user in a variety of ways, such
as through text, graphics, or even sound. Typically, a user interface displays
data in a window where users can manipulate that data and see their
changes directly, as shown in Figure 10-14.
Figure 10-14:
A user
interface
displays
data in a
window that
users can
manipulate
whether
that data
represents
text,
numbers,
pictures, or
sound.
Using any program is like talking to the computer. You first tell the computer
what you want to do (start writing a letter), the computer obeys (loads your
word processor) and then waits for you to do something else. You give
another command to the computer (to format text you just typed), the computer
obeys and then asks what to do next, and so on.
Normally when you give a command to a program, the program responds
right away. However, sometimes the program asks the user for more information.
For example, if you give the command to print a document, the program
may want to know how many pages to print. Whenever a program
needs more information to carry out a command, it displays a dialog box, as
shown in Figure 10-15.