Birmingham | 25-ITP-Sept | Khor Biel | Sprint 1 | coursework/sprint-1

Sprint-1/1-key-exercises/1-count.js

@@ -2,5 +2,12 @@ let count = 0;
 
 count = count + 1;
 
+console.log(count); // should print 1
+
 // Line 1 is a variable declaration, creating the count variable with an initial value of 0
 // Describe what line 3 is doing, in particular focus on what = is doing
+
+
+// On line 3, the code `count = count + 1;` updates the value of the variable `count`. JavaScript first takes the current value stored in `count`, adds `1` to it, and then assigns the new result back into the same variable.
+// The `=` symbol here is the **assignment operator**. It does not mean “equals” in mathematics. Instead, it means “take the value on the right-hand side and store it in the variable on the left-hand side.”
+// After this line runs, `count` now contains the value `1` instead of `0`.

Sprint-1/1-key-exercises/2-initials.js

@@ -5,7 +5,9 @@ let lastName = "Johnson";
 // Declare a variable called initials that stores the first character of each string.
 // This should produce the string "CKJ", but you must not write the characters C, K, or J in the code of your solution.
 
-let initials = ``;
+let initials = `${firstName[0]}${middleName[0]}${lastName[0]}`;
+
+console.log(initials); // should print "CKJ"
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn
 

Sprint-1/1-key-exercises/3-paths.js

@@ -17,7 +17,10 @@ console.log(`The base part of ${filePath} is ${base}`);
 // Create a variable to store the dir part of the filePath variable
 // Create a variable to store the ext part of the variable
 
-const dir = ;
-const ext = ;
+const dir = filePath.slice(0, lastSlashIndex); // dir part is "/Users/mitch/cyf/Module-JS1/week-1/interpret"
+const ext = base.slice(base.lastIndexOf(".")); // ext part is ".txt"
+
+console.log(`The dir part of ${filePath} is ${dir}`); // print: The dir part of /Users/mitch/cyf/Module-JS1/week-1/interpret/file.txt is /Users/mitch/cyf/Module-JS1/week-1/interpret
+console.log(`The ext part of ${filePath} is ${ext}`); // print: The ext part of /Users/mitch/cyf/Module-JS1/week-1/interpret/file.txt is .txt
 
 // https://www.google.com/search?q=slice+mdn

Sprint-1/1-key-exercises/4-random.js

@@ -3,7 +3,22 @@ const maximum = 100;
 
 const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
 
+console.log(num); // Will output numbers like: 5, 42, 87, 100, etc.
+
 // In this exercise, you will need to work out what num represents?
 // Try breaking down the expression and using documentation to explain what it means
 // It will help to think about the order in which expressions are evaluated
 // Try logging the value of num and running the program several times to build an idea of what the program is doing
+
+// Math.random() generates a random decimal between 0 (inclusive) and 1 (exclusive)
+// Examples: 0.1, 0.5, 0.99
+// (maximum - minimum + 1) calculates the range size
+// 100 - 1 + 1 = 100
+// Math.random() * 100 creates numbers from 0 to 99.999...
+// Examples: 0.1 × 100 = 10, 0.5 × 100 = 50, 0.99 × 100 = 99
+// Math.floor() rounds down to the nearest integer
+// Results in integers from 0 to 99
+// + minimum shifts the range
+// Adds 1 to move from 0-99 to 1-100
+// The expression generates a random integer between the minimum value (1) and the maximum value (100), inclusive of both endpoints.
+// Final Answer: num is a random integer from 1 to 100

Sprint-1/2-mandatory-errors/0.js

@@ -1,2 +1,4 @@
-This is just an instruction for the first activity - but it is just for human consumption
-We don't want the computer to run these 2 lines - how can we solve this problem?
+// This is just an instruction for the first activity - but it is just for human consumption
+// We don't want the computer to run these 2 lines - how can we solve this problem?
+
+// We can use comments to "comment out" these lines

Sprint-1/2-mandatory-errors/1.js

@@ -1,4 +1,6 @@
 // trying to create an age variable and then reassign the value by 1
 
-const age = 33;
+let age = 33;
 age = age + 1;
+
+console.log(age);

Sprint-1/2-mandatory-errors/2.js

@@ -1,5 +1,5 @@
 // Currently trying to print the string "I was born in Bolton" but it isn't working...
 // what's the error ?
 
-console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+console.log(`I was born in ${cityOfBirth}`); // moved the console.log below const

Sprint-1/2-mandatory-errors/3.js

@@ -1,9 +1,16 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+const last4Digits = cardNumber.toString().slice(-4);
+
+console.log(last4Digits); // should print 4213
 
 // The last4Digits variable should store the last 4 digits of cardNumber
 // However, the code isn't working
 // Before running the code, make and explain a prediction about why the code won't work
 // Then run the code and see what error it gives.
 // Consider: Why does it give this error? Is this what I predicted? If not, what's different?
 // Then try updating the expression last4Digits is assigned to, in order to get the correct value
+
+
+// Before running the code, I predicted: The code will throw an error because cardNumber is defined as a number (not a string), and numbers don't have a .slice() method.
+// The .slice() method is only available on strings and arrays, not on number primitives
+// To fix the code, we need to convert the number to a string first, then use .slice()

Sprint-1/2-mandatory-errors/4.js

@@ -1,2 +1,4 @@
-const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+const twelveHourClockTime = "20:53";
+const twentyFourHourClockTime = "08:53";
+
+// updated the variable names to be more descriptive

Sprint-1/3-mandatory-interpret/1-percentage-change.js

@@ -2,7 +2,7 @@ let carPrice = "10,000";
 let priceAfterOneYear = "8,543";
 
 carPrice = Number(carPrice.replaceAll(",", ""));
-priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ""));
+priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", "")); // Fixed syntax error by adding missing comma
 
 const priceDifference = carPrice - priceAfterOneYear;
 const percentageChange = (priceDifference / carPrice) * 100;
@@ -20,3 +20,40 @@ console.log(`The percentage change is ${percentageChange}`);
 // d) Identify all the lines that are variable declarations
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+
+
+ // Answers 
+
+// a) Function Calls (5 total):
+
+// carPrice.replaceAll(",", "") (Line 3)
+// Number() (Line 3)
+// priceAfterOneYear.replaceAll(",", "") (Line 4)
+// Number() (Line 4)
+//console.log() (Line 8)
+
+// b) Error Fix:
+
+// Error line: Line 4 - missing comma in .replaceAll("," "")
+// Fix: Change to .replaceAll(",", "")
+// Error type: SyntaxError: missing ) after argument list
+
+// c) Variable Reassignments:
+
+// carPrice = Number(carPrice.replaceAll(",", "")) (Line 3)
+// priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", "")) (Line 4)
+
+// d) Variable Declarations:
+
+//let carPrice = "10,000" (Line 1)
+//let priceAfterOneYear = "8,543" (Line 2)
+// const priceDifference = carPrice - priceAfterOneYear (Line 6)
+// const percentageChange = (priceDifference / carPrice) * 100 (Line 7)
+
+// e) Expression Purpose:
+
+// Number(carPrice.replaceAll(",", "")) converts a formatted currency string with commas into a numeric value for mathematical calculations:
+// Removes commas: "10,000" → "10000"
+// Converts to number: "10000" → 10000
+
+// Output: The percentage change is 14.57 (14.57% price decrease)

Sprint-1/3-mandatory-interpret/2-time-format.js

@@ -23,3 +23,31 @@ console.log(result);
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+
+
+ // Answers:
+
+// a) Variable Declarations: 5
+// movieLength, remainingSeconds, totalMinutes, remainingMinutes, totalHours, result
+
+// b) Function Calls: 1
+// console.log()
+
+// c) movieLength % 60
+//The modulo operator returns the remainder after division
+// This calculates the remaining seconds that don't make a full minute
+
+// d) Line 4: totalMinutes calculation
+// Removes the leftover seconds, then divides by 60 to convert total seconds to minutes
+// Result: Total minutes in the movie
+
+// e) result variable
+// Represents the movie length formatted as HH:MM:SS
+// Better name: formattedDuration or movieDuration
+
+// f) Testing different values
+// ✅ Works for: 3600 (1:00:00), 3661 (1:01:01), 65 (0:01:05)
+// ❌ Issue with: Single-digit minutes/seconds (e.g., 3610 shows 1:10 instead of 1:01:10)
+// Problem: Missing leading zeros for values < 10
+
+// Output: 2:26:24 (2 hours, 26 minutes, 24 seconds)

Sprint-1/3-mandatory-interpret/3-to-pounds.js

@@ -24,4 +24,24 @@ console.log(`£${pounds}.${pence}`);
 // Try and describe the purpose / rationale behind each step
 
 // To begin, we can start with
-// 1. const penceString = "399p": initialises a string variable with the value "399p"
+// 1. const penceString = "399p": initializes a string variable with the value "399p"
+
+
+// const penceString = "399p"
+// Stores original price string with 'p' suffix
+
+// Remove trailing 'p'
+// Uses .substring() to remove the last character
+// "399p" → "399"
+
+// Pad to 3 digits
+// Ensures string has at least 3 digits for consistent parsing
+// "399" → "399" (no change here)
+
+// Extract pounds
+// Takes all digits except last 2 as pounds
+// "399" → "3"
+
+// Extract pence
+// Takes last 2 digits as pence, ensures 2-digit format
+// "399" → "99"

Sprint-1/4-stretch-explore/chrome.md

@@ -16,3 +16,25 @@ Now try invoking the function `prompt` with a string input of `"What is your nam
 
 What effect does calling the `prompt` function have?
 What is the return value of `prompt`?
+
+
+
+Effect of `alert("Hello world!"):`
+
+Shows a popup dialog with "Hello world!" and an OK button
+
+Pauses JavaScript execution until user clicks OK
+
+Effect of `const myName = prompt("What is your name?"):`
+
+Shows a popup dialog with the question, input field, and OK/Cancel buttons
+
+Pauses execution and waits for user input
+
+Return value of `prompt:`
+
+If user types text and clicks OK: returns the input as a string
+
+If user clicks Cancel: returns `null`
+
+The value gets stored in the `myName` variable

Sprint-1/4-stretch-explore/objects.md

@@ -5,12 +5,22 @@ In this activity, we'll explore some additional concepts that you'll encounter i
 Open the Chrome devtools Console, type in `console.log` and then hit enter
 
 What output do you get?
+I got ƒ log() { [native code] } - shows the actual log function code
 
 Now enter just `console` in the Console, what output do you get back?
+Console {} - displays the console object with all its methods
 
 Try also entering `typeof console`
+"object" - confirms console is an object
 
 Answer the following questions:
 
 What does `console` store?
+A built-in browser object that contains logging and debugging methods
+
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+The . is dot notation for accessing object properties
+
+console.log means: access the log method that belongs to the console object
+
+console is the parent object, log is one of its methods/functions