North West | 26-ITP-SEPT | Brian Yorachi | Sprint 2 | Complete Sprint 2 Coursework

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

@@ -1,6 +1,9 @@
 let count = 0;
 
 count = count + 1;
+console.log(count);
 
 // 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 is using the assignment operator (=) to update the value of count.
+// It reads the current value of count, adds 1 to it, and then stores the result back into count.
+// So the value changes from 0 to 1.

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 +17,8 @@ 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, ext });
 
 // https://www.google.com/search?q=slice+mdn

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

@@ -2,8 +2,12 @@ const minimum = 1;
 const maximum = 100;
 
 const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
+console.log(num);
 
 // 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 decimal from 0 up to, but not including, 1.
+// Multiplying by (maximum - minimum + 1) scales the range to 100 possible values.
+// Math.floor() removes the decimal, and adding minimum shifts the result to an integer from 1 to 100.

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

@@ -1,2 +1,7 @@
-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 only for human consumption.
+// We don't want the computer to run these 2 lines - how can we solve this problem?
+//
+// To stop JavaScript from running them, turn them into comments:
+//
+// const age = 33;
+// age = age + 1;

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;
+// Use let instead of const so the value can be reassigned.
 age = age + 1;
+console.log(age);

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

@@ -1,5 +1,6 @@
 // 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";
+// Declare the variable before using it in the template literal.
+console.log(`I was born in ${cityOfBirth}`);

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

@@ -1,5 +1,7 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+// Convert the number to a string before slicing to get the last four digits.
+const last4Digits = String(cardNumber).slice(-4);
+console.log(last4Digits);
 
 // The last4Digits variable should store the last 4 digits of cardNumber
 // However, the code isn't working

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

@@ -1,2 +1,5 @@
-const 12HourClockTime = "8:53pm";
-const 24hourClockTime = "20:53";
+// Variable names cannot begin with a number, so use descriptive names instead.
+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 +12,27 @@ 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
+// There are 5 function calls:
+// - line 4: carPrice.replaceAll(",", "")
+// - line 5: priceAfterOneYear.replaceAll(",", "")
+// - line 4: Number(...)
+// - line 5: 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?
+// The error occurs at line 5 because the syntax is invalid: replaceAll("," "") is missing a comma between the arguments.
+// Fix it by writing replaceAll(",", "").
 
 // c) Identify all the lines that are variable reassignment statements
+// - line 4: carPrice = Number(...)
+// - line 5: priceAfterOneYear = Number(...)
 
 // d) Identify all the lines that are variable declarations
+// - line 1: let carPrice = "10,000";
+// - line 2: let priceAfterOneYear = "8,543";
+// - line 7: const priceDifference = carPrice - priceAfterOneYear;
+// - line 8: const percentageChange = (priceDifference / carPrice) * 100;
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+// It removes the commas from the string, then converts the cleaned string into a number.
+// This is necessary because the prices are stored as strings like "10,000" and "8,543", and we need to perform arithmetic on them.

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

@@ -12,14 +12,25 @@ 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?
+// There are 6 variable declarations: movieLength, remainingSeconds, totalMinutes, remainingMinutes, totalHours, and result.
 
 // b) How many function calls are there?
+// There is 1 function call: console.log(result)
 
 // c) Using documentation, explain what the expression movieLength % 60 represents
+// % is the remainder operator. It gives the remainder when movieLength is divided by 60.
+// For 8784 seconds, 8784 % 60 = 24, so there are 24 seconds remaining after full minutes are counted.
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+// totalMinutes = (movieLength - remainingSeconds) / 60
+// This removes the extra seconds left over after full minutes are taken out, then divides by 60 to convert the remaining whole seconds into total minutes.
+// For 8784 seconds, this gives 146 minutes.
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+// result represents the time formatted as hours:minutes:seconds.
+// A better name could be timeString or formattedTime.
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+// It works for any non-negative number of seconds, because it calculates hours, minutes, and seconds using division and remainders.
+// It will not format correctly for negative values, and it assumes the value is in seconds rather than another unit.

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

@@ -25,3 +25,11 @@ console.log(`£${pounds}.${pence}`);
 
 // To begin, we can start with
 // 1. const penceString = "399p": initialises a string variable with the value "399p"
+// 2. penceString.substring(0, penceString.length - 1): removes the final "p" character so only the digits remain
+// 3. padStart(3, "0"): ensures the value has at least 3 characters by adding leading zeros if needed
+// 4. pounds = the first part of the padded string, excluding the last two digits, so the whole pounds part is preserved
+// 5. pence = the final two digits, padded to 2 characters, to keep a valid pence value
+// 6. console.log(`£${pounds}.${pence}`): prints the formatted result as a pounds and pence string
+
+// For "399p", the steps work like this:
+// "399p" -> "399" -> "399" -> pounds = "3" and pence = "99" -> output "£3.99"

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

@@ -8,8 +8,12 @@ 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?
+It shows a pop-up dialog box with the message "Hello world!" and pauses the browser until the user closes it.
 
 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?
+It displays a dialog box asking the user for input.
+
 What is the return value of `prompt`?
+The return value is the text entered by the user as a string. If the user cancels the prompt, it returns `null`.

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

@@ -13,4 +13,11 @@ Try also entering `typeof console`
 Answer the following questions:
 
 What does `console` store?
+`console` stores the browser's debugging object. It contains methods such as `log`, `error`, `warn`, and `assert` that let us print values and inspect program state.
+
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+The `.` is the property access operator. It means "look inside the `console` object and use the `log` or `assert` method stored there".
+So `console.log(...)` means “call the `log` method on the `console` object”.
+
+Try also entering `typeof console`.
+This returns `"object"`, because `console` is an object containing methods.