Cape Town | 26-ITP | Quentin Gwele | Sprint 2 | Coursework-2

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

@@ -4,3 +4,5 @@ count = count + 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
+
+// Line 3 takes the current value of count (0), adds 1 to it (0 + 1 = 1), and uses the assignment operator (=) to reassign and store this new value (1) back into the count variable.

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

@@ -5,6 +5,7 @@ const 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.
 
-const initials = ``;
+const initials = firstName[0] + middleName[0] + lastName[0];
 
+console.log(initials);
 // https://www.google.com/search?q=get+first+character+of+string+mdn

Sprint-2/1-key-exercises/3-paths.js

@@ -17,7 +17,9 @@ 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);
+const ext = filePath.slice(filePath.lastIndexOf("."));
 
+console.log(dir);
+console.log(ext);
 // https://www.google.com/search?q=slice+mdn

Sprint-2/1-key-exercises/4-random.js

@@ -3,7 +3,13 @@ const maximum = 100;
 
 const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
 
-// 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
+console.log(num);
+// what does num represent?
+// num represents a random whole number (integer) between minimum (1) and maximum (100) inclusive.
+
+//Breakdown of the expression:
+// 1. Math.random() generates a decimal number from 0 (inclusive) up to, but not including, 1.
+// 2. (maximum - minimum + 1) calculates the range size (100 - 1 + 1 = 100).
+// 3. Math.random() * 100 scales the random decimal to a range between 0 and 99.999...
+// 4. Math.floor() rounds that value down to the nearest whole integer (0 to 99).
+// 5. + minimum (+ 1) shifts the final value up into the target range of 1 to 100. 

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

@@ -1,2 +1,2 @@
-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?

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

@@ -1,5 +1,7 @@
 // Currently trying to print the string "I was born in Bolton" but it isn't working...
 // what's the error ?
+// Answer: cityOfBirth was referenced before it was declared (ReferenceError).
 
-console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+console.log(`I was born in ${cityOfBirth}`);
+

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

@@ -1,6 +1,8 @@
-const cardNumber = 4533787178994213;
+const cardNumber = "4533787178994213";
 const last4Digits = cardNumber.slice(-4);
 
+console.log(last4Digits);
+
 // 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

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

@@ -1,2 +1,5 @@
-const 12HourClockTime = "8:53pm";
-const 24hourClockTime = "20:53";
+const twelveHourClockTime = "8:53pm";
+const twentyFourHourClockTime = "20:53";
+
+console.log(twelveHourClockTime);
+console.log(twentyFourHourClockTime);

Sprint-2/3-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(",", ""));
 
 const priceDifference = carPrice - priceAfterOneYear;
 const percentageChange = (priceDifference / carPrice) * 100;
@@ -12,11 +12,20 @@ console.log(`The percentage change is ${percentageChange}`);
 // Read the code and then answer the questions below
 
 // a) How many function calls are there in this file? Write down all the lines where a function call is made
+// Answer: There are 5 function/method calls across 3 lines:
+// - Line 4: replaceAll(",", "") and Number(...)
+// - Line 5: replaceAll(",", "") and Number(...)
+// - Line 10: console.log(...)
 
-// b) Run the code and identify the line where the error is coming from - why is this error occurring? How can you fix this problem?
+// b) Run the code and identify the line where the error is coming from – why is this error occurring? How can you fix this problem?
+// Answer: On line 5, there is a typo in replaceAll(",", "") where the comma is outside the quotes or contains empty space before the closing quote (""")). 
+// Fix line 5 by changing it to: priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", ""));
 
 // c) Identify all the lines that are variable reassignment statements
+// Answer: Lines 4 and 5 (carPrice = ... and priceAfterOneYear = ...)
 
 // d) Identify all the lines that are variable declarations
+// Answer: Lines 1, 2, 7, and 8 (let carPrice, let priceAfterOneYear, const priceDifference, const percentageChange)
 
-// e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+// e) Describe what the expression Number(carPrice.replaceAll(",", "")) is doing – what is the purpose of this expression?
+// Answer: .replaceAll(",", "") removes the comma from the price string ("10,000" becomes "10000"), and Number(...) converts that clean string into a numeric value so mathematical calculations can be performed on it

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

@@ -12,14 +12,19 @@ console.log(result);
 // For the piece of code above, read the code and then answer the following questions
 
 // a) How many variable declarations are there in this program?
+// Answer: 6 variable declarations (movieLength, remainingSeconds, totalMinutes, remainingMinutes, totalHours, result).
 
 // b) How many function calls are there?
+// Answer: 1 function call (console.log(result)).
 
 // c) Using documentation, explain what the expression movieLength % 60 represents
-// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
+// Answer: % is the remainder (modulo) operator. It calculates the leftover seconds when movieLength is divided into full minutes (60-second chunks).
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+// Answer: It subtracts the leftover seconds from the total movie length to get a exact multiple of 60, then divides by 60 to convert that duration into whole minutes.
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+// Answer: It represents the movie length formatted as a HH:MM:SS time string. A clearer name would be formattedTime or formattedMovieLength.
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+// Answer: It works for all non-negative numbers representing total seconds. However, if movieLength is negative or not a number (e.g., a string or null), it will output invalid time values or NaN.

Sprint-2/3-mandatory-interpret/3-to-pounds.js

@@ -23,5 +23,14 @@ console.log(`£${pounds}.${pence}`);
 // You need to do a step-by-step breakdown of each line in this program
 // 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": Initialises a string variable with the value "399p" representing the price in pence including the trailing letter 'p'.
+
+// 2. const penceStringWithoutTrailingP = penceString.substring(0, penceString.length - 1): Extracts the numeric portion of the pence string by taking characters from index 0 up to (but not including) the last character, removing the 'p' ("399").
+
+// 3. const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0"): Ensures the pence string is at least 3 digits long by adding leading zeros if necessary (e.g., "5" becomes "005"), ensuring there are enough digits to extract both pounds and pence.
+
+// 4. const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2): Extracts the pounds portion of the price by taking all digits except the last two ("3").
+
+// 5. const pence = paddedPenceNumberString.substring(paddedPenceNumberString.length - 2).padEnd(2, "0"): Extracts the last two digits representing pence ("99") and ensures it is padded to 2 digits.
+
+// 6. console.log(`£${pounds}.${pence}`): Formats and prints the final price string with the pound symbol, pounds amount, period, and pence amount ("£3.99").

Sprint-2/4-stretch-explore/chrome.md

@@ -8,8 +8,10 @@ Let's try an example.
 In the Chrome console, invoke the function `alert` with one argument, the string `"Hello world!"`;
 
 What effect does calling the `alert` function have?
-
+Answer: Calling alert("Hello world!") displays a pop-up dialog box in the browser window containing the message "Hello world!" and an "OK" button that pauses script execution until dismissed.
 Now try invoking the function `prompt` with a string input of `"What is your name?"` - store the return value of your call to `prompt` in an variable called `myName`.
-
 What effect does calling the `prompt` function have?
+Answer: Calling prompt("What is your name?") displays a pop-up dialog box containing the message, a text input field, an "OK" button, and a "Cancel" button.
+
 What is the return value of `prompt`?
+Answer: It returns the string entered by the user in the input field when they click "OK". If the user clicks "Cancel" or closes the dialog, it returns null.

Sprint-2/4-stretch-explore/objects.md

@@ -5,12 +5,18 @@ 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?
+Answer: It outputs the function definition itself, showing `ƒ log() { [native code] }`.
 
 Now enter just `console` in the Console, what output do you get back?
+Answer: It returns the `console` object containing various built-in properties and logging methods.
 
 Try also entering `typeof console`
+Answer: It outputs `"object"`.
 
 Answer the following questions:
 
 What does `console` store?
+Answer: `console` is a built-in global object that stores properties and methods used to output messages, errors, and warnings to the browser console.
+
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+Answer: The dot (`.`) is the property accessor operator. It is used to access specific methods (`log`, `assert`) attached to the `console` object.