CompTIA A+ Certification All-in-One Exam Guide

2. The if statement checks to see if the animal variable contains a value
of “cat”.
3. If that’s the case, the computer will print the word “meow” to the
command prompt. If not, then nothing will happen.
In this case, the script would never print “meow” because the condition
was not met.
Conditionals are a critical building block for most scripts and programs.
One of the main reasons to write a script in the first place is because you need
to do something many times. In programming, a good way to accomplish this
is with a loop. Basic loops are another kind of conditional, but tell the
computer to run the code over and over until the condition is (or is not) met.
Depending on the language, you’ll usually see loops indicated with keywords
like for and while. Here’s an example:
This loop will run until the number of cows is 4, so it will print “moo”
four times—one for each cow. Because the cows variable has an integer
value, we can do math with it. Each time the loop runs, it prints “moo” once,
and adds one to the number of cows.
EXAM TIP Different languages have different control structures. Most of
them have at least a few. This section looked at two—if statements and loops
—but the CompTIA A+ objectives only expect you to identify basic loops.
Comments
Scripting and programming languages usually have a way to insert special
text—called a comment—that helps anyone reading the script later (including
the writer, a few months on!) understand what’s going on. The computer
ignores this text, as it’s only for the humans. Leaving comments is a really