Classroom Notes: 1.2 Programming Constructs

A variable is a named storage location in a computer's memory that holds a value or piece of data.

Computer programming is the process of writing step-by-step instructions called code for a computer to follow so that it can perform specific tasks or solve problems.

The three basic structures that control the computer program are:

• Sequence: Executing instructions in a step-by-step order.
• Selection (Decision): Making choices using if-then-else conditions.
• Iteration (Repetition/Loops): Repeating a set of instructions using loops like for or while.

Iterators (and loops) are useful because they:

• Save time and effort by eliminating the need to write the same line of code over and over.
• Make code cleaner and easier to read or update.

• Addition (+): Adds numbers together (e.g., 5 + 3).
• Subtraction (-): Subtracts one number from another (e.g., 10 - 4).
• Multiplication (*): Multiplies numbers (e.g., 4 * 2).
• Division (/): Divides numbers (e.g., 20 / 4).
• Modulus (%): Finds the remainder after integer division (e.g., 7 % 3 gives 1).

The commonly used comparison or relational operators in programming are:

• Equal to (==): Checks if two values are equal.
• Not equal to (!=): Checks if two values are not equal.
• Greater than (>): Checks if the left value is larger.
• Less than (<): Checks if the left value is smaller.
• Greater than or equal to (>=): Checks if the left value is larger or equal.
• Less than or equal to (<=): Checks if the left value is smaller or equal.

• Integer (int): Whole numbers without decimals (e.g., 42, -5).
• Float / Real (float): Numbers with a decimal point (e.g., 3.14, 0.5).
• String (str): Text, words, or characters inside quotes (e.g., "Hello", "Class 6").
• Boolean (bool): Logical values that are either True or False.