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Activity 1.8 Intermediate Data Types and Operations

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Introduction

Activity 1.8

Intermediate Data Types and Operations

Topics

  • Escape Sequences
  • Constants
  • Compound Assignment Operators
  • Increment and Decrement Operators
  • Math Constants and Functions

Escape Sequences

An escape sequence is a special combination of characters that tells a computer to do something other than what those characters normally do.

In JavaScript, an escape sequence starts with a backslash (\) followed by another character.

For example, the sequence \n doesn't print a backslash and the letter 'n'. Instead, the backslash "escapes" the usual meaning of the 'n' and tells the program to insert a new line.

Escape Sequences

  • \n Newline
  • \\ Backslash literal
  • \" Double-Quote literal
  • \t Tab
  • \' Single-Quote literal

Constants

A constant is a variable whose value, once assigned, cannot be changed. It's used to store data that should remain the same throughout a program's execution.

Constants

You define a constant using the const keyword. The convention is to name constants using all uppercase letters, with words separated by underscores. 

const TAX_RATE = 0.08;
...
let total = subtotal * TAX_RATE;

Why Use Constants

Readability: Using a descriptive name like PI or MAX_CONNECTIONS is much clearer than using a "magic number" like 3.14159 or 100.

Preventing Errors: Since the value can't be changed after initialization, you're protected from accidentally overwriting it later in your code.

Compound Assignment Operators

Compound assignment operators provide a concise way to perform an operation on a variable and then assign the new value back to that same variable.

+= -= *= /= %=
Addition Assignment: x = x + 5 -> x += 5
Subtraction Assignment: x = x - 5 -> x -= 5
Multiplication Assignment: y = y * 2 -> y *= 2
Divison Assignment: y = y / 2 -> y /= 2
Modulus Assignment: y = y % 2 -> y %= 2

Increment and Decrement Operators

The increment (++) and decrement (--) operators are a shorthand way to add or subtract 1 from a variable. These are frequently used in loops and counters. 

let x = 5;
let y = 5;
x++; // x becomes 6
y--; // y becomes 4

Math Constants and Functions

JavaScript contains a collection of functions and constants for performing common mathematical operations.

Constants:
Math.PI
Represents the mathematical constant PI (Ď€), approximately 3.14159.

Math Constants and Functions

Functions:
Math.round(num)
Round a decimal number to the nearest whole number.
Math.floor(num)
Round a decimal number down to the nearest whole number.
Math.ceil(num)
Round a decimal number up to the nearest whole number.

Math Constants and Functions

Math.sqrt(num)
Returns the positive square root of num. Example: Math.sqrt(25) returns 5.0.

Math Constants and Functions

Math.random()
Returns a random number value greater than or equal to 0.0 and less than 1.0 (~0.9999).
Example: Math.floor((Math.random() * 10) + 1 returns a random integer between 1 and 10.

'F' → Fullscreen

Objectives

  • icon Practice implementing various JavaScript constructs:
    • icon Escape sequences
    • icon Constants
    • icon Compound assignment operations
    • icon Increment & decrement operations
    • icon Math constants and functions
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Activity Tasks

  • icon Create a new project named 1-8-intermediate-data.js.
  • icon Complete each task individually.

Task 1: Increment, Decrement, and Compound Assignment

1-8-intermediate-data.js
console.log("--- Task 1: Increment, Decrement, and Compound Assignment ---");


let score = 10;
console.log("Initial score: " + score);


// Compound assignment
score += 5;
console.log("Score after += 5: " + score);


// Increment operator
score++;
console.log("Score after ++: " + score);


// Decrement operator
score--;
console.log("Score after --: " + score);


alert("Press Enter to continue...");
// -----------------------------------------------------------------------------
//

Task 2: Math Constants and Functions

1-8-intermediate-data.js
19 collapsed lines
console.log("--- Task 1: Increment, Decrement, and Compound Assignment ---");


let score = 10;
console.log("Initial score: " + score);


// Compound assignment
score += 5;
console.log("Score after += 5: " + score);


// Increment operator
score++;
console.log("Score after ++: " + score);


// Decrement operator
score--;
console.log("Score after --: " + score);


alert("Press Enter to continue...");
// -----------------------------------------------------------------------------


console.log("--- Task 2: The Math Object and Constants ---");


let radius = 5;


// Calculate area using Math.PI Math.pow()
let area = Math.PI * Math.pow(radius, 2);
console.log("Area of circle with radius " + radius + ": " + area);


// Generate a random dice roll (1-6)
let diceRoll = Math.floor(Math.random() * 6) + 1;
console.log("Random dice roll: " + diceRoll);


alert("Press Enter to continue...");
// -----------------------------------------------------------------------------
//

Task 3: Escape Sequences

1-8-intermediate-data.js
34 collapsed lines
console.log("--- Task 1: Increment, Decrement, and Compound Assignment ---");


let score = 10;
console.log("Initial score: " + score);


// Compound assignment
score += 5;
console.log("Score after += 5: " + score);


// Increment operator
score++;
console.log("Score after ++: " + score);


// Decrement operator
score--;
console.log("Score after --: " + score);


alert("Press Enter to continue...");
// -----------------------------------------------------------------------------


console.log("--- Task 2: The Math Object and Constants ---");


let radius = 5;


// Calculate area using Math.PI Math.pow()
let area = Math.PI * Math.pow(radius, 2);
console.log("Area of circle with radius " + radius + ": " + area);


// Generate a random dice roll (1-6)
let diceRoll = Math.floor(Math.random() * 6) + 1;
console.log("Random dice roll: " + diceRoll);


alert("Press Enter to continue...");
// -----------------------------------------------------------------------------


console.log("--- Task 3: Escape Characters ---");


// Using tab (\t) for formatting
let table = "Item\t\tPrice\nKeyboard\t$75\nMouse\t\t$25";
console.log(table);


// Using newline (\n) and quotes (\")
let message = "He said, \"Hello, world!\"\nAnd the program responded, 'Hi.'";
console.log(message);


alert("Press Enter to continue...");
// -----------------------------------------------------------------------------
//

Task 4: Combining Concepts

1-8-intermediate-data.js
47 collapsed lines
console.log("--- Task 1: Increment, Decrement, and Compound Assignment ---");


let score = 10;
console.log("Initial score: " + score);


// Compound assignment
score += 5;
console.log("Score after += 5: " + score);


// Increment operator
score++;
console.log("Score after ++: " + score);


// Decrement operator
score--;
console.log("Score after --: " + score);


alert("Press Enter to continue...");
// -----------------------------------------------------------------------------


console.log("--- Task 2: The Math Object and Constants ---");


let radius = 5;


// Calculate area using Math.PI Math.pow()
let area = Math.PI * Math.pow(radius, 2);
console.log("Area of circle with radius " + radius + ": " + area);


// Generate a random dice roll (1-6)
let diceRoll = Math.floor(Math.random() * 6) + 1;
console.log("Random dice roll: " + diceRoll);


alert("Press Enter to continue...");
// -----------------------------------------------------------------------------


console.log("--- Task 3: Escape Characters ---");


// Using tab (\t) for formatting
let table = "Item\t\tPrice\nKeyboard\t$75\nMouse\t\t$25";
console.log(table);


// Using newline (\n) and quotes (\")
let message = "He said, \"Hello, world!\"\nAnd the program responded, 'Hi.'";
console.log(message);


alert("Press Enter to continue...");
// -----------------------------------------------------------------------------


console.log("--- Task 4: Challenge Task (Combining Concepts) ---");


let totalStudents = 15;
const GRADE_INCREASE = 1.05;
let newGrade = 80;


// Compound assignment with a constant
newGrade *= GRADE_INCREASE;


// Round the grade using Math.round()
let roundedGrade = Math.round(newGrade);


console.log(`Out of ${totalStudents} students,`);
console.log(`the new rounded grade is: ${roundedGrade}.`);
//
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Sample Output

Your program output should something similar to the sample output below.

Sample Output
--- Task 1: Increment, Decrement, and Compound Assignment ---
Initial score: 10
Score after += 5: 15
Score after ++: 16
Score after --: 15
Press Enter to continue... [Enter]
--- Task 2: The Math Object and Constants ---
Area of circle with radius 5: 78.53981633974483
Random dice roll: 6
Press Enter to continue... [Enter]
--- Task 3: Escape Characters ---
Item            Price
Keyboard        $75
Mouse           $25
He said, "Hello, world!"
And the program responded, 'Hi.'
Press Enter to continue... [Enter]
--- Task 4: Challenge Task (Combining Concepts) ---
Out of 15 students,
the new rounded grade is: 84.
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Reflection Questions

You may write your reflection answers as comments at the bottom of your code.

  1. Think about the concept of compound assignment. What is a real-world scenario (outside of a programming context) where you might perform a similar "shortcut" operation—where you update a value by combining it with another? For example, is there a situation where you keep a running total of expenses by adding each new cost to your existing total, rather than recalculating from scratch each time?
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Submission

Submit your activity and reflection answers to the appropriate dropbox.

Activity Complete