London | 25-ITP-Jan | Kayanat Suleman | Sprint 1 | Structuring and Testing Data

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

@@ -4,3 +4,7 @@ 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
+// The '=' assignment operator. It assigns the value on the right hand side to the variable on the left.
+// The variable 'count' is initially assigned the value of 0.
+// And the result is assigned back to count.
+// This mean 'count; is updated each time this line runs.

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

@@ -5,7 +5,11 @@ 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);
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn
-
+// Explaning the solution: I assign 'initials' to a new string variable made by combining the 
+// first character of 'firstName', 'middleName' and 'lastName'.
+// Strings in JavaScript are indexable, so using [0] accesses the first 
+// character of each string.

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

@@ -12,12 +12,19 @@
 const filePath = "/Users/mitch/cyf/Module-JS1/week-1/interpret/file.txt";
 const lastSlashIndex = filePath.lastIndexOf("/");
 const base = filePath.slice(lastSlashIndex + 1);
+const lastDotIndex = filePath.lastIndexOf(".");
 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(lastDotIndex + 1);
 
-// https://www.google.com/search?q=slice+mdn
+console.log("Dir:", dir);
+console.log("Ext:", ext);
+// https://www.google.com/search?q=slice+mdn
+// Explaining the solution: lastIndexOf() is used to locate boundaries (/ and .)
+// slice() is used to extract the required parts of the string.
+// No values are hard-coded, so the solution works for similar file paths.
+// The result correctly seperats the path into dir and ext.

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

@@ -2,8 +2,13 @@ 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
+// Explaning the solution: console.log(num); returns a number.
+// Upon investigation Math.Floor - returns and whole int that is the less than or equal to its numeric argument. 
+// Math.randon - returns a random float/int
+// Now putting my understanding together - I understand that the const num when logged using console.log returns a value in this order 
+// A number at random is chosen and is multiplied with the maximum value (of that number) - the minimum value is then added to one (+ 1) and then added to the minimum of the total. 

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

@@ -1,4 +1,8 @@
 // trying to create an age variable and then reassign the value by 1
 
-const age = 33;
+let age = Math.floor(Math.random());
 age = age + 1;
+console.log(age);
+// Explaning the solution: Assigning age to a variable that is not constant - then utalising Math.Floor and Math.Random to assign age a whole random number.
+// I then allow age to be added to 1
+// I then log to the console to verify the 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}`);

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

@@ -1,9 +1,12 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+const last4Digits = cardNumber.toString().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
 // 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
+// Prediction: The code may not work due to the const variable being an int. The slice method usually works on strings. 
+// Updating the const last4Digits with .toString() allowed the const cardNumber to convert from int to string and therefore the solution works as expected.

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

@@ -1,2 +1,6 @@
-const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+const twelveHourClockTime = "20:53";
+const twentyFourHourClockTime = "08:53";
+
+console.log(twelveHourClockTime);
+console.log(twentyFourHourClockTime);
+//Explaining the solution: The issue is that the syntax to assign a const var needs to be a string.

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(",", ""));
 
 const priceDifference = carPrice - priceAfterOneYear;
 const percentageChange = (priceDifference / carPrice) * 100;
@@ -11,12 +11,24 @@ 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
+// a) How many function calls are there in this file? 
+// 1) carPrice.replaceAll(",", "")
+// 2) Number(carPrice.replaceAll(",", ""))
+// 3) priceAfterOneYear.replaceAll(",", "")
+// 4) Number(priceAfterOneYear.replaceAll(",", ""))
+// 5) console.log(`The percentage change is ${percentageChange}`);
 
 // 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 syntax error is originating on line 5, this error occurs because replaceAll is missing ',' in between the arguments -  priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," , ""));.
 
 // c) Identify all the lines that are variable reassignment statements
+// carPrice = Number(carPrice.replaceAll(",", ""));
+// priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", ""));
 
 // d) Identify all the lines that are variable declarations
+// The lines that are variable declarations use let or const: let carPrice, let priceAfterOneYear, const priceDifference and const percentageChange.
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+// This particular expression is doing two steps. First it takes "10,000" and removes the commas so the output then is "10000"
+// The second step converts the the string into a number - this is likely because the next function then subtracts the number to find the difference between 
+// carPrice and priceAfterOneYear and stores it within priceDifference variable declaration. 

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

@@ -1,4 +1,4 @@
-const movieLength = 8784; // length of movie in seconds
+const movieLength = -4382.3817; // length of movie in seconds
 
 const remainingSeconds = movieLength % 60;
 const totalMinutes = (movieLength - remainingSeconds) / 60;
@@ -12,14 +12,32 @@ 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?
+//This program has 6 variable declarations:
+//const movieLength = 8784;
+//const remainingSeconds = movieLength % 60;
+//const totalMinutes = (movieLength - remainingSeconds) / 60;
+//const remainingMinutes = totalMinutes % 60;
+//const totalHours = (totalMinutes - remainingMinutes) / 60;
+//const result = `${totalHours}:${remainingMinutes}:${remainingSeconds}`;
 
 // b) How many function calls are there?
+// There is 1 function call within this program
+//1) 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
+// The modulus operator returns the remainder after dividing movieLength by 60.
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+// remainingSeconds removes leftover seconds 
+// movieLength - remainingSeconds leave only full seconds
+// Dividing by 60 converts seconds to minutes 
+// This expression converts the total movie length from seconds into whole minutes, excluding any leftover second. 
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+// The variable result represents the formatted movie duration into hours, minutres and seconds. 
+// A better variable name may be: movieDuration
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+// Upon experimenting with the const movieLength I have tested edge cases. The code works well for positive integer values.
+// Handling edge cases such as negative value, floats lead to confusing results.

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

@@ -25,3 +25,23 @@ console.log(`£${pounds}.${pence}`);
 
 // To begin, we can start with
 // 1. const penceString = "399p": initialises a string variable with the value "399p"
+
+// 2. const penceStringWithoutTrailingP = penceString.substring( 0, penceString.length - 1);
+// penceString.length -1: points to the index just before the last character. The substring(0, ect) takes everything from the start up to the last character (but not including the last character)
+// The result removes the trailing "p" so the output becomes "399p" --> "399"
+
+// 3. const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");: 
+// Ensures the pence int has at least 3 characters by adding leading zeros if required.
+// This is useful for values under 100p so the pounds/pence split works accurately.
+
+// 4. const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2);
+// This takes everything except the last two digits
+// The last two digits represent the pence, so whatever is left over from the calculation is the pounds.
+
+// 5. const pence = paddedPenceNumberString.substring(paddedPenceNumberString.length - 2).padEnd(2, "0");
+// The substring(paddedPenceNumberString.length - 2) takes the last two characters of the padded string (e.g. "399") and extacts the pence portion "99"
+// The .padEnd(2, "0") ensures the pence part is always 2 digits by adding trailing zeros if needed.
+// In most cases there are already two digits, however part of the code protects against outputs such as "3" becoming "30" which would be an inaccurate outcome.
+
+// 6. console.log(`£${pounds}.${pence}`);
+// Prints the final formatted price in pounds and pence. An example would be "399p" would print as "£3.99