Question

Give meaningful identifiers for the following variables. a. A variable to store the first name of a student. b. A variable to store the discounted price of an item. c. A variable to store the number of juice bottles. d. A variable to store the number of miles traveled. e. A variable to store the highest test score.

Short answer

a. studentFirstName; b. discountedPrice; c. juiceBottleCount; d. milesTraveled; e. highestTestScore.

Step-by-step solution

Identify the characteristics of the variable

For each variable, determine what type of data it needs to hold or describe. This will help shape our identifier by focusing on the information type, scale, and context.

Consider scope and purpose

Think about where each variable might be used in a program or system. Understanding if it's local or global, temporary or important for longer periods can influence the identifier length and specificity.

Create descriptive identifiers

Combine insights from Steps 1 and 2 into descriptive names that convey context and meaning, making the program more understandable.

Refine for clarity and brevity

Ensure each identifier is concise, avoiding unnecessary words while still providing enough detail for clarity to anyone reading the code later.

Key concepts

Identifier Selection

When selecting an identifier for a variable, it is essential that the name reflects the data the variable holds. The identifier should be descriptive enough to give insight into what the variable represents, yet concise to avoid cluttering code. For example, if you are naming a variable for storing the first name of a student, a suitable identifier could be `firstName`. This name is clear, straightforward, and precisely encapsulates the variable's purpose without any ambiguity. Here are a few tips for selecting good identifiers:

• Use meaningful words that reflect the variable's role, like `discountedPrice` for an item’s reduced cost.
• Avoid generic names like `data`, `value`, or `temp`, as they do not convey useful information.
• Keep the identifier short but descriptive enough to be intelligible to anyone reading your code.
• If the variable represents a count or collection of items, such as the number of juice bottles, use plurals like `juiceBottlesCount` or `numJuiceBottles`.

Data Types

Understanding data types is a cornerstone of effective variable naming. Data types indicate the kind of value a variable will hold, such as integers, strings, or floating-point numbers. Choosing the right data type is crucial because it affects how the data can be manipulated and used in calculations.

• Ensure that the data type matches the content it needs to store. For example, if you need to store a price that could have decimal points, opt for a floating-point type.
• Use integer types for counts and quantities, such as the number of juice bottles or miles traveled, because these are whole numbers.
• String types are typically used for text data like names or labels, making `firstName` a perfect candidate for a string variable.
• Make sure your choice of data type aligns with the computational needs of your variables, optimizing for both performance and storage.

Scope and Purpose

The scope of a variable determines where it is accessible within the code, while its purpose dictates why it exists. Understanding scope and purpose aids in deciding the lifespan and visibility of a variable.

• Local variables are used within a function or small block of code. They are temporary and fulfill a specific task, making them suitable for short, specific identifiers.
• Global variables are accessible from any part of the program. They must have unique and descriptive names to prevent conflicts and ensure clarity.
• Think about how widely a variable will be used. If a `highestTestScore` variable needs to interact across various functions, its scope should be broad enough to facilitate these interactions.
• Purposeful names aid in understanding both what a variable is used for and its significance within the code. This clarity can prevent future errors and improve collaboration between developers.

Code Clarity

Code clarity is about ensuring your code can be easily understood by others, including your future self. It is not just about naming variables correctly but also about writing clean and organized code.

• Use clear and consistent naming conventions. If you follow the camelCase method for naming, ensure it's applied uniformly throughout your codebase, such as `numMilesTraveled`.
• Reduce complexity by breaking down large functions or procedures into smaller, more manageable ones, with variables named appropriately for each purpose.
• Document your code where necessary. Although names like `numJuiceBottles` are self-explanatory, complex logic might need brief comments to explain its purpose.
• Adopting these practices can dramatically improve the comprehensibility and maintainability of your code, facilitating a primer coding experience for yourself and others checking your work.