Working with Arrays, Loops, and Conditional Statements - HTML, CSS, and Dynamic HTML - page 875

Teamwork: The Danger of Spaghetti Code
Spaghetti code is a pejorative programming term that refers to convoluted or poorly
written code. One hallmark of spaghetti code is the frequent branching from one section
of code to another, making it difficult to track the program line-by-line as it is executed.
A change in one part of the program could lead to unpredictable changes in a completely
different section of the code.
Most developers discourage the use of break , continue , and label statements unless
absolutely necessary. They can confuse a programmer trying to debug code in which a
program loop can end before its stopping condition, or code in which statements are not
processed in the order that they are written in a document. Almost all of the tasks you
perform with these statements also can be performed by carefully setting up the conditions
for program loops.
Even with the best of intentions, spaghetti code easily can occur in environments in
which the same code is maintained by several people or passed from one employee to
another. Each programmer adds a particular feature that is needed today without ade-
quately documenting the changes made to the code, and without considering the impact of
those changes on the larger program.
To avoid or at least reduce the occurrence of spaghetti code, you always should docu-
ment your code and develop a structure that is easy to follow. Break up tasks into smaller
functions that are easier to manage and can be reused in other parts of your programs.
Also, avoid global variables whenever possible because a change in the value of a global
variable can have repercussions throughout the entire code. Instead, use local variables
with their scope limited to small, compact functions. If a variable must be used elsewhere
in your code, it should be passed as a parameter value with the meaning and purpose of
the parameter well documented within the program.
By practicing good coding techniques, you can make your programs more accessible to
your colleagues and make it easier to pass your code on to your successors.
Session 12.3 Quick Check
1. What is a conditional statement? What is the most commonly used conditional
statement?
2. What code writes the text Internet Explorer Browser to the document if the
Boolean variable WebBrowser equals true ?
3. The WebBrowser variable has been changed to a text string variable that can
equal either IE or Mozilla . Write an if else statement to display the text
Internet Explorer Browser if the WebBrowser variable equals IE , and to display
Mozilla Browser if otherwise.
4. The WebBrowser variable can now equal IE , Opera , Safari , or Firefox . Write a
series of else if statements that write the name of the browser to the docu-
ment. If WebBrowser equals none of the four text strings listed above, write the
text Generic Browser to the document.
5. Answer the previous question using a switch statement. Use a break statement
to break off from processing the switch statement once a match has been found.
6. What command extracts the day of the week value from a Date object variable
named thisDate ?
7. What command can be used to break out of the current iteration in a for loop?
8. What command forces a script to go to the next iteration of the current
program loop?