programming-for-dummies

Spaghetti Programming without a Plan 31
The rest of this chapter discusses programming techniques based on problems
encountered by programmers working in the real world. Basically, computer
scientists keep developing and refining programming techniques after they see
what really works and what doesn’t.
Spaghetti Programming without a Plan
In the early days of programming, most programs were fairly short and
simple. A typical program might just calculate a mathematical equation,
which to a computer, is just a little more challenging than adding two numbers
together.
Book I
Chapter 2
Different Methods
for Writing
Programs
To write such small, single-task programs, programmers would typically
start typing commands in their favorite programming language with little
planning, just to write a program quickly.
Unfortunately, many programs aren’t just written once and then used forever.
If a program isn’t working exactly right, or if the program needs to do
something new that the original programmer didn’t include, you must take
an existing program and modify it.
Modifying an existing program sounds simple, but it’s not. First, you must
understand how the program works so you’ll know exactly how to modify
that program. If you try modifying a program without understanding how it
works, there’s a good chance you could wreck the program and keep it from
working, much like ripping out cables from your car engine without knowing
what you’re really doing.
After you understand how a program works, the second step involves writing
new commands into the existing program. Now, here’s where the problem
occurs. Take an existing program and modify it once. Now take that same program
and modify it again. Now take that same program and modify it 20 more
times, and what do you get? Most likely, you’ll have a mish-mash collection of
code that works, but isn’t organized logically, as shown in Figure 2-1.
Modifying a program several times by yourself might not be so bad because
you probably remember what you changed and why. But what happens if
seven other programmers modify the same program seven different times
and then none of them are around to help you understand what changes
they made? If you guessed you’ll wind up with a bigger mess than before,
you’re right.