London | May 2025 | Victoria Scott | Sprint 1 Coursework

Sprint-1/1-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 updates the value of the variable count by increasing it by 1. The expression on the right side of the = adds 1 to the current value of count, and the result is then stored back into count. The = symbol is an assignment operator. It takes the value on the right-hand side and assigns it to the variable on the left-hand side. In this case, it means take the result of count + 1 and assign it to count. = does not mean equality, like in mathematics; it means assignment in programming.

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

@@ -5,7 +5,7 @@ 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];
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn
 

Sprint-1/1-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

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

@@ -7,3 +7,5 @@ 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
+
+// The variable num stores a random whole number between 1 and 100. The code uses Math.random() to get a number between 0 and 1. It then multiplies that number to get a value between 0 and 100. Math.floor() rounds it down to a whole number. Finally, it adds 1 so the result is between 1 and 100. Each time you run the code, num will be a different number in that range.

Sprint-1/2-mandatory-errors/0.js

@@ -1,2 +1,4 @@
 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?
+We don't want the computer to run these 2 lines - how can we solve this problem?
+
+// To stop the computer from running those two lines, we can turn them into comments by adding // at the beginning of each line. This tells the computer to ignore the line because it is only meant for humans to read.

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

@@ -2,3 +2,8 @@
 
 const age = 33;
 age = age + 1;
+
+// The code does not work because const creates a variable that cannot be changed. Since we want to increase the value of age, we should use let instead of const. This allows us to reassign the value of the variable:
+
+let age = 33;
+age = age + 1;

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

@@ -3,3 +3,7 @@
 
 console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+
+// You need to declare the variable before you use it. Code should look like this:
+const cityOfBirth = "Bolton";
+console.log(`I was born in ${cityOfBirth}`);

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

@@ -7,3 +7,12 @@ const last4Digits = cardNumber.slice(-4);
 // 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
+
+// I predict this code will not work because cardNumber is a number, not a string, and .slice() is a method that only works on strings or arrays. Since numbers don’t have a .slice() method, it will likely throw a TypeError.
+// Ran the code, error message: TypeError: cardNumber.slice is not a function
+// As predicted. .slice doesn't work on numbers. .slice() is a string method, and cardNumber is a number. 
+// Corrected code:
+const cardNumber = 4533787178994213;
+const last4Digits = cardNumber.toString().slice(-4);
+console.log(last4Digits);
+

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

@@ -1,2 +1,7 @@
 const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+const 24hourClockTime = "08:53";
+
+// There is an error in the variable name 12HourClockTime because JavaScript does not allow variable names to start with a number. 
+// Corrected code:
+const twelveHourClockTime = "20:53";
+const twentyFourHourClockTime = "08:53";

Sprint-1/3-mandatory-interpret/1-percentage-change.js

@@ -12,11 +12,39 @@ 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 is a total of 5 function calls:
+
+carPrice.replaceAll(",", "")
+Number(...)
+priceAfterOneYear.replaceAll("," "") 
+Number(...) 
+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?
+// This line has a syntax error:
+priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ""));
+// The problem is that there’s a missing comma between ("," and "")
+// /By adding a comma the code is correct:
+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
 
+let carPrice = "10,000";
+
+let priceAfterOneYear = "8,543";
+
+const priceDifference = carPrice - priceAfterOneYear;
+
+const percentageChange = (priceDifference / carPrice) * 100;
+
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+
+//carPrice.replaceAll(",", "") removes all the commas from the string turning it into 10000. Number(...) converts that string into a number so that you can do math with it.
+

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

@@ -12,14 +12,20 @@ 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?
+// 6
 
 // b) How many function calls are there?
+// 1
 
 // c) Using documentation, explain what the expression movieLength % 60 represents
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
+// Remainder operator. It gives the number of seconds left after converting to full minutes.
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+// Line 4 takes the total seconds in the movie, removes the leftover seconds, and divides by 60 to get the total number of full minutes.
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+// result represents the movie length written as hours:minutes:seconds. formattedMovieLength could be a better name for this variable.
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+// It works for most normal, positive whole numbers, but may not work well with negative or non-integer values.

Sprint-1/3-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. const penceStringWithoutTrailingP = penceString.substring(0, penceString.length - 1);: This removes the last character ("p") from the string. penceString.length - 1 gives the position of the last character. substring(0, ...) gets everything from the start up to (but not including) the "p".
+// 3. const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0"); : Makes sure the string has at least 3 characters by adding zeros at the beginning if necessary. This is to ensure there is always enough digits to split into pounds and pence.
+// 4. const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2); : Takes all but the last two digits to get the pounds part of the price.e.g. "399" = "3".
+// 5. const pence = paddedPenceNumberString : substring(paddedPenceNumberString.length - 2) / padEnd(2, "0"); - This gets the last two digits — the pence part — and makes sure it’s always 2 digits e.g. "399" = "99".
+// 6. console.log(`£${pounds}.${pence}`); : This puts everything together into pounds and pence format.
+
+
+

Sprint-1/4-stretch-explore/chrome.md

@@ -11,8 +11,9 @@ In the Chrome console,
 invoke the function `alert` with an input string of `"Hello world!"`;
 
 What effect does calling the `alert` function have?
+// Calling the alert function causes a popup message box to appear in the browser window. This box displays the message "Hello world!", and the user must click “OK” to close 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?
-What is the return value of `prompt`?
+What effect does calling the `prompt` function have? Calling the prompt function shows a popup asking "What is your name?" and a text input field asking the user to enter text, and click "ok" or "cancel". 
+What is the return value of `prompt`? The return value of prompt is the text the user types, as a string, or null if they click "Cancel". The result can be stored in a variable, myName, to be used later in the program.

Sprint-1/4-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?
+ƒ log() { [native code] }
 
 Now enter just `console` in the Console, what output do you get back?
+console {debug: ƒ, error: ƒ, info: ƒ, log: ƒ, warn: ƒ, ...}
 
 Try also entering `typeof console`
 
 Answer the following questions:
 
 What does `console` store?
-What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+console stores a collection of functions (methods) used for displaying messages and debugging.
+What does the syntax `console.log` or `console.assert` mean? In particular, 
+
+what does the `.` mean? console is the object.
+.log or .assert refers to a a function stored inside that object.The '.' is used to access a specific function (or property) inside the console object.