CS2 Module 1
Variables & Functions
In programming, a variable is a container that stores data values. A function is a block of code designed to perform a particular task.
Example: In JavaScript, you might declare a variable and a function like this:
let userName = "Alice"; // variable declaration
function greetUser(name) { // function declaration
return "Hello, " + name + "!";
}
console.log(greetUser(userName)); // Output: Hello, Alice!
Loops & Arrays
A loop is a programming structure that repeats a sequence of instructions until a specific condition is met. An array is a data structure that contains a collection of elements, typically of the same data type.
Example: Using a for loop to iterate through an array:
let colors = ["red", "green", "blue"]; // array declaration
for (let i = 0; i < colors.length; i++) { // loop through array
console.log("Color " + (i+1) + ": " + colors[i]);
}
Objects & Classes
An object is a collection of properties and methods that represent a real-world entity. A class is a blueprint for creating objects with predefined properties and methods.
Example: Creating a class and object in JavaScript:
class Car { // class declaration
constructor(brand, model) {
this.brand = brand;
this.model = model;
}
displayInfo() {
return this.brand + " " + this.model;
}
}
let myCar = new Car("Toyota", "Camry"); // object creation
console.log(myCar.displayInfo()); // Output: Toyota Camry
Inheritance & Debug
Inheritance is a mechanism where a new class inherits properties and methods from an existing class. Debug is the process of finding and resolving bugs or defects in software.
Example: Class inheritance and debugging:
class Vehicle {
constructor(name) {
this.name = name;
}
}
class Car extends Vehicle { // inheritance
constructor(name, wheels) {
super(name);
this.wheels = wheels;
}
}
// Debugging with console.log
let myCar = new Car("Tesla", 4);
console.log(myCar); // Debug output to check object properties
Source Code & Syntax
Source code is the fundamental component of a computer program that is created by a programmer. Syntax refers to the set of rules that defines the combinations of symbols that are considered to be correctly structured programs in a language.
Example: Source code with correct syntax:
// This is source code in Python
def calculate_area(length, width): # Correct syntax
"""Calculate rectangle area"""
area = length * width
return area
result = calculate_area(5, 3)
print("Area:", result) # Output: Area: 15
Compile & IDE
To compile means to convert source code written in a high-level programming language to a lower-level language (e.g., assembly language, machine code). An IDE (Integrated Development Environment) is a software application that provides comprehensive facilities to computer programmers for software development.
Example: Compiling Java code using an IDE like IntelliJ IDEA:
// Java source code
public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, World!");
}
}
// Compile command: javac HelloWorld.java
// Run command: java HelloWorld
