Computer Fundamentals Module 2: Variables in C++

Computer Fundamentals and Programming - Module 2: Declaring Variables

• Objectives: Students will identify and explain data types in C++. They will learn how to declare variables in C++, including syntax. Students will understand variable scope (local vs. global) and its impact on program accessibility. Students will apply declared variables in calculations and expressions.

Comments

• Importance: Comments are crucial in programming, improving code readability and maintainability. They explain code functionality, provide notes for programmers, and temporarily disable code during debugging in C++.

Single-Line Comments

• Syntax: Single-line comments begin with //. Everything that follows // on the same line is disregarded by the compiler.

Multi-Line Comments

• Syntax: Multi-line comments start with /* and end with */. These comments can span multiple lines, useful for lengthy explanations.

Variables

• Definition: A variable is a named storage location in memory that holds a value.

• Declaration in C++: C++ Variables must be declared before use specifying its type and name.

Common Data Types

• Integer: Stores whole numbers (e.g., int age = 25;).

• Floating-Point: Stores numbers with decimal points (e.g., float price = 19.99f;, double distance = 12345.6789;). float is single precision, double is double precision.

• Character: Stores a single character (e.g., char initial = 'A';).

• Boolean: Stores truth values (true or false) (e.g., bool isStudent = true;).

cout

• Definition: cout is a C++ object used for displaying data to the console. It's part of the iostream library.

• Syntax: cout << expression;. The << is the stream insertion operator directing output to the cout stream.

Common Uses of cout

• Displays text (strings enclosed in double quotes).
• Displays variable values.
• Combines text and variables in a single output statement.

Arithmetic Operators

• Types: C++ uses operators for mathematical actions on variables and values. Common operators include addition (+), subtraction (-), multiplication (*), division (/), and modulus (%).

• Modulus: The remainder after division.

Examples

• Specific examples of declaring integer, float, and character variables were provided in the slides.

• Code examples showing use of cout statements to display variable values were included.

• Examples of arithmetic operators and how to use them were illustrated in the slides.

• Examples of how endl and \n work in code were included.

Additional Topics (problems for program)

• Converting currencies (pesos to dollars)
• Calculating geometric shapes (rectangles, circles)
• Calculating employee salary based on weekly hours and daily rate.