Fundamentals of Variables in C Programming

In this post, we’ll explore the basics of variables and constants in C programming. Additionally, we will learn to declare, initialize, and use them effectively, thereby enhancing code performance and functionality.

What are variables?

In C programming, variables store data temporarily during program execution in named memory locations. They have a specific data type and can hold various types of values, such as integers, floating-point numbers, characters, etc.

Basically, we could say that a variable is a container (storage area) to hold data.

Breakdown of Variable Syntax in C

The syntax of a variable can be divided in three ways:

• Declaration of a Variable
• Definition of a Variable
• Initialization of a Variable

Variable Declaration in C

• In the C programming language, variable declaration is the process of having a variable’s name and type defined prior to its first usage in the program. This action informs the compiler about the type of data that will be stored in the variable, thus ensuring that the necessary memory space is allocated for it.

• The syntax for the variable declaration is as follows:

• The C declaration syntax shown below explicitly specifies the name and type of the variable; furthermore, you can declare multiple variables of the same type in a single line by separating them with commas.

data_type variable_name;                        // defines a single variable
            OR
data_type variable_Name1, variable_Name2;    // defines multiple variables

where:

• data_type: specifies the type of data that the variable will hold (such as int, float, char, etc.)
• variable_name: specifies the name given to the variable.
• value: specifies the value assigned to the variable that will be stored.

For example:

int age;           // Declares a variable named "age" of type integer
float salary;     // Declares a variable named "salary" of type float
char grade;      // Declares a variable named "grade" of type character

Variable Definition in C

• Variable declarations and definitions are similar in C programming, but variable definitions also involve allocating memory and sometimes initializing a value. In order to define a variable, it must first be declared and initialized.

These are the standard syntax for defining variables:

datatype variable_name = value;

• The ‘datatype’ (such as int, float, char, etc.) indicates the kind of data that the variable will contain.
• ‘variable_name’ is the name given to the variable.
• ‘value‘ is the initial value assigned to the variable.

We can define multiple variables of the same type in a single line by separating them with commas

datatype variable1 = value1, variable2 = value2, variable3 = value3;

For example:

int number1 = 30, number2 = 90, sum = number1 + number2; <br>// Defines three int variables and initializes them with values

Variable Initialization in C

• In C programming, variable initialization entails assigning an initial value to a variable during its declaration or definition. This process is crucial since it guarantees that variables possess valid values prior to their usage in the program.
• You can also initialize variables during the declaration:

datatype variable_name; = value;              

For example:

int age = 25;
float salary = 1000.50;
char grade = 'A';

Initialization after Declaration: The assignment operator (=) can also be used to initialize variables after they have been declared.

variable_name = value;

For example:

int age;   //Declaration
age = 34;  //Initialization after Declaration

NOTE:

Since C is a strongly-typed language, it is imperative that all variable types must be specified before using them in a program or code.

Variable Naming Conventions

Programming languages such as C have variable naming conventions, which are rules or guidelines that programmers adhere to in order to name variables in a logical and consistent way.

Developer cooperation, maintainability, and code clarity are all enhanced by following naming conventions. Common variable naming conventions in C programming include:

• Make use of meaningful names: Make sure the variable names you choose accurately convey the function or content of the variable. Steer clear of obscure or single-letter names.

• Use lowercase letters: Variable names in C conventionally use lowercase letters to improve readability.

• Use underscores to separate words (snake_case): If a variable name consists of multiple words, use underscores (_) to separate them. For example: developer_name, total_sum, is_valid.

• Steer clear of reserved keywords: Avoid using standard library function names or C keywords (such as int, float, and char) as variable names.

• Maintain coherence: Keep the codebase’s naming conventions consistent. When naming variables with similar types or purposes, follow the same convention.

• Constants in UPPERCASE: Constants, which are variables whose values remain unchanged during program execution/runtime, are often named using all uppercase letters with underscores separating words. For example: MIN_SIZE, PI_VALUE, DEFAULT_COLOR, YOUR_HEIGHT.

Use camelCase for function names: In C, variables should not be written in camelCase, which capitalizes the words that follow a lowercase letter.

In our next blog post we will delve deeper into variable scope in C programming, click here