Manchester | 26-ITP-Sep | Rahana Suleiman | Sprint 2 | Complete Sprint 2 Coursework

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

@@ -2,5 +2,15 @@ let count = 0;
 
 count = count + 1;
 
+
+//const 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
+
+//ANSWER:
+
+// Line 3 is reassigning the value of count. This is because we are using "let" and not "const" which allows us to reassign values.  The value of count is being evaluated first (count + 1), which sums up to (0 + 1 = 1) and then it is updated using the assignment operator (=), which takes the result and stores it 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 = `${firstName.charAt(0)}${middleName.charAt(0)}${lastName.charAt(0)}`;
+console.log(initials);
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn

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

@@ -15,9 +15,13 @@ const base = filePath.slice(lastSlashIndex + 1);
 console.log(`The base part of ${filePath} is ${base}`);
 
 // Create a variable to store the dir part of the filePath variable
+const dir = filePath.slice(0, lastSlashIndex);
+
 // Create a variable to store the ext part of the variable
+const lastDotIndex = filePath.lastIndexOf(".");
+const ext = filePath.slice(lastDotIndex);
 
-const dir = ;
-const ext = ;
+console.log(`The dir part of ${filePath} is ${dir}`);
+console.log(`The ext part of ${filePath} is ${ext}`);
 
-// https://www.google.com/search?q=slice+mdn
+// https://www.google.com/search?q=slice+mdn

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

@@ -1,9 +1,31 @@
-const minimum = 1;
-const maximum = 100;
-
-const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
+const minimum = 1; // Sets the lowest possible number that can be generated
+const maximum = 100; // Sets the highest possible number that can be generated
 
 // 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
+
+const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
+
+/*
+EXPLANATION IN ORDER OF EXECUTION (OPERATOR PRECEDENCE):
+
+1. (maximum - minimum + 1) — Grouping Parentheses (Highest Precedence):
+   Calculates the total number of possible whole values between minimum and maximum, inclusive (e.g., 100 - 1 + 1 = 100 possible values).
+
+2. Math.random() — Function Call:
+   Generates a random floating-point decimal from 0 up to (but not including) 1.
+
+3. Math.random() * (maximum - minimum + 1) — Multiplication:
+   calculates the total number of possible values between minimum and maximum, (but not including) 100 (e.g., 0 to 99.999...).
+
+4. Math.floor(...) — Function Call:
+   Rounds the decimal down to the nearest whole integer, converting the range from [0, 99.999...] to an integer from 0 to 99.
+
+5. + minimum — Addition (Lowest Precedence):
+   Shifts the whole set of numbers up so that the lowest outcome becomes `minimum` (1) instead of 0, resulting in a whole number between 1 and 100 inclusive.
+*/
+
 // 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); // num represents a random whole number between 1 and 100 inclusive

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 just for human consumption
+ We don't want the computer to run these 2 lines - how can we solve this problem?*/
+
+
+//ANSWER:
+
+// We comment them out

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

@@ -1,4 +1,11 @@
 // trying to create an age variable and then reassign the value by 1
 
-const age = 33;
+// The problem here is that 'const' creates a constant variable which cannot be reassigned, attempting to reassign (age = age + 1) throws a TypeError: Assignment to constant variable.
+
+
+//change 'const' to 'let' so the value can be updated
+// const age = 33;
+let age = 33;
 age = age + 1;
+
+// console.log(age);

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

@@ -1,5 +1,12 @@
 // 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}`);
+// The error is a ReferenceError: Cannot access 'cityOfBirth' before initialization 
+// In JavaScript variables declared with 'const' or 'let' cannot be accessed before they are declared or initialized
+
+
+//SOLUTION
+// move the variable declaration above the 'console.log()'
 const cityOfBirth = "Bolton";
+
+console.log(`I was born in ${cityOfBirth}`);

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

@@ -1,9 +1,22 @@
-const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
-
 // 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
+
+//Prediction: The code won't work because cardNumber is stored as a Number and not a string, this is because '.slice()' is a string method 
+// Numbers in JavaScript don't work with '.slice()'
+
+
 // Then run the code and see what error it gives.
+//This is the error it gives: TypeError: cardNumber.slice is not a function
+
+
 // Consider: Why does it give this error? Is this what I predicted? If not, what's different?
+
+//Explanation: Yes, my prediction was accurate. JavaScript threw a TypeError because '.slice()' is a string method 
 // Then try updating the expression last4Digits is assigned to, in order to get the correct value
+// Keep the original number value untouched
+const cardNumber = 4533787178994213;
+// Convert to string dynamically before slicing
+const last4Digits = cardNumber.toString().slice(-4);
+
+console.log(last4Digits); // output 4213

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

@@ -1,2 +1,7 @@
-const 12HourClockTime = "8:53pm";
-const 24hourClockTime = "20:53";
+// JavaScript variable names cannot start with a number. They must start with an alphabet(A-Z), an underscore(_), or a dollar sign($). JavaScript is also case sensitive so they have to use camelCase, PascalCase, among others.
+
+const twelveHourClockTime = "8:53pm";
+const twentyFourHourClockTime = "20:53";
+
+// console.log(HourClockTime);
+// console.log(hourClockTime);

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 +12,22 @@ 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 along 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?
+// ANSWER: The error comes from Line 5 because a comma is missing between the two string arguments in replaceAll("," "").
+// FIX: Add the missing comma to 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 (using let and const)
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+// ANSWER: The expression Number(carPrice.replaceAll(",","")) removes the comma from the carPrice = "10,000" and converts it to "10000". 
+// Then, JavaScript can now convert the string into a number so it can be calculated.
+

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

@@ -12,14 +12,27 @@ 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. 
+// (movieLength, remainingSeconds, totalMinutes, remainingMinutes, totalHours, and result — all declared using const)
 
 // b) How many function calls are there?
+// ANSWER: There is only 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: The expression movieLength % 60 uses the remainder (%) operator to calculate the number of seconds remaining that can't form a full seconds (8784 % 60 = 24 seconds)
+
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+// ANSWER: The expression `(movieLength - remainingSeconds) / 60` calculates the exact number of full minutes. 
+// First, `(movieLength - remainingSeconds)` subtracts the remaining seconds from the total seconds to leave a clean multiple of 60. 
+// Then, dividing that result by 60 converts those remaining seconds into whole minutes (8760 / 60 = 146 minutes).
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+// ANSWER: A better name for the variable would be 'formattedDuration' because it clearly describes that the variable stores the movie duration in a formatted hours, minutes, and seconds format.
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+
+// ANSWER: No. It breaks if movieLength is negative (giving negative time) or a string. 
+// Additionally, single-digit minutes or seconds (e.g., 4 minutes, 8 seconds) output as "2:4:8" instead of standard "02:04:08" formatting.

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

@@ -24,4 +24,9 @@ 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": Initialises a string variable with the value "399p".
+// 2. const penceStringWithoutTrailingP: Uses substring() to remove the trailing "p" from "399p", leaving "399".
+// 3. const paddedPenceNumberString: Uses padStart() to ensure the string is at least 3 digits long by adding leading "0"s if needed (e.g., "5" becomes "005"), ensuring there are enough digits to extract both pounds and pence.
+// 4. const pounds: Uses substring() to remove/discard the final two digits (which represent the pence) and keep everything before them, extracting the whole pounds value ("3").
+// 5. const pence: Uses substring() to extract only the final two digits ("99") for the pence value, using padEnd() as a safeguard to keep it at two digits.
+// 6. console.log(`£${pounds}.${pence}`): Uses template literals to format and display the final price string ("£3.99").