Learn to Program with C_ Learn to Program using the Popular C Programming Language ( PDFDrive )

Chapter 2 ■ C – The Basics
2.3.4 Some Naming Conventions
Other than the rules for creating identifiers, C imposes no restriction on what names to use, or
what format (uppercase or lowercase, for instance) to use. However, good programming practice
dictates that some common-sense rules should be followed.
An identifier should be meaningful. For example, if it’s a variable, it should reflect the value
being stored in the variable; netPay is a much better variable than x for storing someone’s net
pay, even though both are valid. If it’s a function (Chapter 7), it should give some indication of
what the function is supposed to do; playGame is a better identifier than plg.
It is a good idea to use upper and lowercase combinations to indicate the kind of item named
by the identifier. In this book, we use the following conventions:
• A variable is normally written in lowercase: for example, sum. If we need
a variable consisting of two or more words, we start the second and
subsequent words with an uppercase letter: for example, voteCount or
sumOfSeries.
• A symbolic (or named) constant is an identifier that can be used in place of
a constant such as 100. Suppose 100 represents the maximum number of
items we wish to process in some program. We would probably need to use
the number 100 in various places in the program. But suppose we change
our mind and want to cater for 500 items. We would have to change all
occurrences of 100 to 500. However, we would have to make sure that we
do not change an occurrence of 100 used for some purpose other than the
maximum number of items (in a calculation like principal*rate/100).
• To make it easy to change our mind, we can set the identifier MaxItems to
100 and use MaxItems whenever we need to refer to the maximum number
of items. If we change our mind, we would only need to set MaxItems to the
new value. We will begin a symbolic constant with an uppercase letter. If it
consists of more than one word, we will begin each word with uppercase, as
in MaxThrowsPerTurn.
• We will see how to use symbolic constants in Section 4.6.
2.4 Basic Data Types
In Section 1.4 we briefly touched on the concept of a data type. For most of this book, we will use
the following data types:
int, double, and char
These, among others, are referred to as primitive data types.
Each data type defines constants of that type. When we declare a variable to be of a particular
type, we are really saying what kind of constants (values) can be stored in that variable. For
example, if we declare the variable num to be int, we are saying that the value of num at any time
can be an integer constant such as 25, -369, or 1024.
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