Java Reference
In-Depth Information
the programming process
A
program
(also referred to as an application) is a set of instructions targeted to solve a particular
problem that can be unambiguously understood by a computer. To this end, the computer will
translate the program to the language it understands, which is machine language consisting
of 0s and 1s. Computers execute a program literally as it was programmed, nothing more and
nothing less. Programming is the activity of writing or coding a program in a particular pro-
gramming language. This is a language that has strict grammar and syntax rules, symbols, and
special keywords. People who write programs are commonly referred to as programmers or
application developers. The term software then refers to a set of programs within a particular
business context.
An example of a programming exercise is a program that calculates the body mass index (BMI) of
a person. The BMI is calculated by dividing a person's weight in kilograms by the square of his or
her height in meters. A person is con-
sidered overweight if his or her BMI
is over 25. A BMI calculator program
then requires the weight and height as
inputs and calculates the associated
BMI as the output. This is illustrated in
Figure 1-1. This BMI example is used
to demonstrate the steps in the software
development cycle.
Inputs
Output
Height
PROGRAM
BMI
Weight
figure 1-1
Programs are typically written using a
step-by-step approach, as follows:
1.
Requirements gathering and analysis
2.
Program design
3.
Program coding
4.
Translation to machine language
5.
Testing and debugging
6.
Deployment
7.
Maintenance
Because our environment is continuously evolving,
software, too, is often continually reviewed and
adapted. Therefore, these steps are often represented
as a cycle, as shown in Figure 1-2, rather than as a
ladder.
Requirements
Maintenance
Design
Coding
Deployment
The first step is to make sure you understand the problem
in sufficient detail. This means analyzing the problem
statement carefully so you fully grasp all the require-
ments that need to be fulfilled by the software program.
This may involve Q&A sessions, interviews, and surveys
Testing
Translation
figure 1-2
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