London | 26-ITP-Sep | Rhoda Ajiroba | Sprint 2 | JavaScript Fundamentals

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

@@ -3,4 +3,4 @@ let count = 0;
 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 adds 1 to the current value of count and assigns the new value back to count. The = is the assignment operator.

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

@@ -5,6 +5,6 @@ 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];
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn

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

@@ -17,7 +17,7 @@ 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 = base.slice(base.lastIndexOf(".") + 1);
 
-// https://www.google.com/search?q=slice+mdn
+// https://www.google.com/search?q=slice+mdn

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

@@ -7,3 +7,7 @@ const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
 // 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
+// num represents a random whole number between 1 and 100 inclusive.
+// Math.random() generates a random number from 0 up to, but not including, 1.
+// The calculation scales this to the required range, Math.floor() rounds it down,
+// and adding minimum makes the range start at 1.

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

Sprint-2/2-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}`);

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

@@ -1,5 +1,5 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+const last4Digits = cardNumber.toString().slice(-4);
 
 // 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 +1,2 @@
-const 12HourClockTime = "8:53pm";
-const 24hourClockTime = "20:53";
+const twelveHourClockTime = "8:53pm";
+const twentyFourHourClockTime = "20:53";

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 +12,21 @@ 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 calls.
+// Line 4: carPrice.replaceAll() and Number()
+// Line 5: priceAfterOneYear.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?
+// Answer: The error was on line 5 because a comma was missing between the two arguments
+// passed to replaceAll(). Adding the missing comma fixes the error.
 
 // c) Identify all the lines that are variable reassignment statements
+// Answer: Lines 4 and 5 are variable reassignment statements.
 
 // d) Identify all the lines that are variable declarations
+// Answer: Lines 1, 2, 7 and 8 are variable declarations.
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+// Answer: It removes all commas from the carPrice string and converts the result into a number.
+// This allows carPrice to be used in mathematical calculations.

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

@@ -12,14 +12,24 @@ 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: There are 6 variable declarations.
 
 // b) How many function calls are there?
+// Answer: There is 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: movieLength % 60 gives the remainder after dividing movieLength by 60.
+// This represents the remaining seconds after converting the time into whole minutes.
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+// Answer: It subtracts the remaining seconds from movieLength and divides by 60.
+// This gives the total number of whole minutes in the movie.
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+// Answer: result represents the movie length formatted as hours, minutes and seconds.
+// A better variable name would be formattedMovieLength.
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+// Answer: No, it will not format all values correctly.
+// For example, single-digit minutes or seconds will not have a leading zero.

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

@@ -2,13 +2,13 @@ const penceString = "399p";
 
 const penceStringWithoutTrailingP = penceString.substring(
   0,
-  penceString.length - 1
+  penceString.length - 1,
 );
 
 const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
 const pounds = paddedPenceNumberString.substring(
   0,
-  paddedPenceNumberString.length - 2
+  paddedPenceNumberString.length - 2,
 );
 
 const pence = paddedPenceNumberString
@@ -25,3 +25,8 @@ console.log(`£${pounds}.${pence}`);
 
 // To begin, we can start with
 // 1. const penceString = "399p": initialises a string variable with the value "399p"
+// 2. Removes the trailing "p" from penceString, changing "399p" to "399".
+// 3. Pads the pence string with leading zeros so it has at least 3 characters.
+// 4. Extracts all digits except the last two to get the pounds part of the price.
+// 5. Extracts the last two digits to get the pence part and ensures it has two digits.
+// 6. Formats the pounds and pence as a price and prints it to the console.