Variables in Pseudocode

In programming, variables are essential for storing and manipulating data. Let's explore variables step-by-step in this guide. We’ll break it down into easy-to-follow concepts that will help you understand how to declare, assign, and use them effectively in pseudocode.

1. Variable Declaration

Before you can use a variable, you need to declare it. Think of it as introducing a new character in a story. You’re telling the computer, "Hey, I’m going to use this character (variable) in my program."

Syntax:

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  • Identifier: This is the name you give to the variable, like counter or totalScore.
  • Data type: This tells the computer what kind of data the variable will hold (e.g., INTEGER, REAL, STRING).

2. Identifiers and Data Types

An identifier is just a fancy term for the variable name. In pseudocode, identifiers follow these rules:

  • They must begin with a letter.
  • They can contain letters, digits, or underscores (_).
  • They cannot contain special characters (like @ or #).

Data Types determine what kind of information your variable will store. Common data types include:

  • INTEGER: For whole numbers (e.g., 5, -10).
  • REAL: For decimal numbers (e.g., 4.75, -2.1).
  • STRING: For text (e.g., "Hello World").
  • BOOLEAN: For true/false values (e.g., TRUE, FALSE).
  • CHAR: For a single character (e.g., ‘A’, ‘5’).

Example:

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  • isStudent will store a Boolean value (TRUE or FALSE).
  • grade holds a single character, such as ‘A’.
  • temperature is a real number with decimals.

3. Variable Assignment

Once you declare a variable, you need to give it a value, like telling the computer, "Here’s the actual data for this character."

In pseudocode, you assign a value to a variable using the assignment operator ← (fancy arrow pointing left). Think of it as the computer "taking" a value and putting it in a variable.

Note: For our IDE, we will use "<-" (i.e. less than sign along with minus sign) instead of ←. The main reason for this change is that ← symbol is not present in normal keyboards, hence may be difficult to use this symbol when writing pseudocode.

Syntax:

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Example:

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  • We just assigned "Alice" to userName, 25 to userAge, and 89.5 to score.

4. Constants

A constant is similar to a variable, but its value never changes. Once assigned, it’s locked in for the rest of the program. Constants are often used for values that remain the same, like mathematical values (e.g., Pi) or fixed rates (e.g., tax rate).

Syntax:

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Example:

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  • Pi and MaximumScore are constants. Their values won’t change.

Now that you know the basics of variables, declarations, data types, assignments, and constants, you're ready to handle more complex operations with them! Remember, variables help keep track of information in your programs, and constants lock important values in place. Happy coding!