Lecture

Key Expressions for Variables and Constants

In programming, declaration refers to informing the compiler or interpreter about the name and type of something you intend to use later, such as a variable or function.

For example, in the C language, int a; is a declaration that informs about creating an integer variable named a.

In TypeScript, you can declare a constant to store a boolean value, like const isDev: boolean;, which informs about a constant named isDev.

Naming refers to the act of giving meaningful names to these variables, functions, etc.

For instance, names like userName and calculateTotal are self-explanatory about their purpose at just a glance.

The difference between a good developer and a less skilled one starts showing in their ability to name things effectively.

A great developer crafts understandable names and follows consistent naming conventions like camelCase (e.g., isLoggedIn) or snake_case (e.g., user_name) to enhance code readability and maintainability.

Naming Convention

Most programming languages do not allow spaces in variable names, so developers implicitly follow specific naming conventions when naming files, variables, and constants.

The four main naming conventions are:

Camel case (or Lower camel case)
Pascal case (or Upper camel case)
Snake case
Kebab case

Let's compare each naming method.

1. Camel case

Generally refers to lower camel case, where the first word is in lowercase and the first letter of subsequent words is capitalized.

Examples: totalPurchaseCount, setCurrentValue
Features: The capitalized words look like the humps of a camel, hence the name.
Usage: Used in languages like JavaScript, Java for variable and function names.

2. Pascal case

Also known as Upper camel case, where the first letter of every word is capitalized.

Examples: TotalPurchaseCount, SetCurrentValue
Features: Similar to camel case but starts with a capital letter in the first word as well.
Usage: Used for class names, component names, and database table names in languages like Java, C#, TypeScript, etc.

3. Snake case

All letters are in lowercase, with words separated by underscores (_).

Examples: total_purchase_count, set_current_value
Features: Named for resembling a snake slithering along.
Usage: Used for variable and function names in Python, constants in C, and certain database field names.

4. Kebab case

All letters are in lowercase, with words separated by hyphens (-).

Examples: total-purchase-count, set-current-value
Features: Originates from the resemblance to kebab skewers with words strung together.
Usage: Used for CSS class names/IDs, URLs, package names, HTTP headers, etc.

Now let's explore key English expressions related to declaration, assignment, and naming together.

Quiz

0 / 1

Camel case is a naming convention where the first letter of every word is capitalized.

True

False

Key Expressions for Declaration and Naming

declare a (variable/function/class)

Declare a boolean variable. Declare a boolean variable.

declare is a verb meaning 'to declare.' The noun form is declaration. Since variable, function, and class are countable nouns, an article is needed.

define

Define a new environment variable. Define a new environment variable.

define is used when a variable is both declared and assigned a value (initialized). Unlike declare, it assigns memory.

assign a value to a variable

Assign 5 to an integer variable. Assign 5 to an integer variable.

assign is a verb used to assign a value to a variable. Since value and variable are countable nouns, an article is needed.

initialize a variable

Initialize a variable to 0. Initialize a variable to 0.

initialize is the verb used when declaring a variable and setting its initial value. This is the American spelling; the British spelling is initialise.

reassign a value

Reassign a new value to the variable. Reassign a new value to the variable.

reassign is used to overwrite a new value onto a variable that already has a value.

unassign a value

Unassign the value from the variable. Unassign the value from the variable.

unassign is used to remove or clear a value that has been assigned to a variable.

clear the value of a variable

Clear the assigned value of the variable. Clear the assigned value of the variable.

clear is used to empty a stored value in a variable or field, returning it to its initial state.

allocate memory to a variable

Allocate memory to the new variable. Allocate memory to the new variable.

allocate is used to assign computing resources or memory to a specific target, commonly used with the preposition to.

deallocate or release resources

Release the memory assigned to the variable. Release the memory assigned to the variable.

deallocate or release is used to return memory or resources that are no longer in use.

name a (variable/function/class)

Name a variable in camel case. Name a variable in camel case.

name as a noun means 'name', and as a verb, it means 'to give a name.' When mentioning naming conventions, the expression in [case] is used.

rename

Rename a global variable. Rename a global variable.

rename is a verb used when assigning a new name to an element that already has an existing name.