London | May 2025 | Houssam Lahlah | Acoursework/sprint 2

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

@@ -2,5 +2,6 @@ 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 Take the current value of count, and then add 1, and store the result back in count.

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.charAt(0) + middleName.charAt(0) + lastName.charAt(0);
+
+console.log(initials);
+
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn
 

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

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

@@ -3,7 +3,74 @@ const maximum = 100;
 
 const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
 
-// 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
+// 1- In this exercise, you will need to work out what num represents?
+
+// the num gives a random whole number between 1 and 100 like 73, 12, or 100.
+
+// 2- Try breaking down the expression and using documentation to explain what it means
+/*
+
+1. Math.random()
+
+Returns a random decimal number between 0 and 1 but never gives 1.0.
+
+Example: 0.24 
+
+2. (maximum - minimum + 1)
+
+This gives number of possible values.
+
+Without the +1, we'd only get the difference, not the full count.
+
+for example:
+
+5 - 1 = 4 → but there are actually 5 numbers: 1, 2, 3, 4, 5
+
+So we add +1 to include both ends of the range.
+
+3. Math.random() * (maximum - minimum + 1)
+
+This gives a random decimal number between 0 and 100 (like 24, 65 ...)
+
+Because we want the random decimal scaled to the size of the range of possible values.
+
+For example, if we want a number between 1 and 100 (inclusive), there are 100 possible numbers (1, 2, ..., 100).
+
+Multiplying by 100 means the decimal is scaled up to cover all those possibilities before rounding.
+
+4. Math.floor(...)
+
+This rounds the decimal down to the nearest whole number.
+
+Example: Math.floor(78.43) → 78
+
+5. + minimum
+
+we add the minimum to shift the range correctly, and make sure the random number up to start from minimum.
+
+5-1- for example if we remove the + minimum 
+
+5-1-1 Math.random() 0.9999 * 99 + 1 → only goes up to 99.999... → max = 99.999... → floor = 100 (but very unlikely) 
+
+now 100 becomes very hard to reach, and in many cases, you never get it.
+
+5-1-2 Math.random() 0.00 * 99 + 1 → only goes up to 0... → max = 0... → floor = 0 (now the minimum is 0, and can appears) 
+
+conclusion : when we don’t add + minimum, there is a chance that 1 appears, but it’s not the guaranteed minimum anymore — 
+
+and the range starts at 0, not 1.
+
+5-2- when we add +minimum 
+
+now we make sure the min and max can appear in the final results and make sure the minimum is 1 not 0. 
+
+Minimum appears when random = 0
+
+Maximum appears when random is almost 1 (like 0.9999...).
+
+example : Math.random() * 99 + 1 → up to 0.99 → max = 99 → floor = 99 → +1 = 100 (so more possibilities for 100 to appears) 
+
+*/
+
+//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

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

@@ -1,4 +1,5 @@
-// trying to create an age variable and then reassign the value by 1
+// Trying to create an age variable and then reassign the value by 1
 
-const age = 33;
-age = age + 1;
+let age = 33;          // Declare a variable called age and assign it the value 33
+age = age + 1;         // Reassign age to be its current value plus 1
+console.log(age);      // Output: 34

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

@@ -10,9 +10,17 @@ Let's try an example.
 In the Chrome console,
 invoke the function `alert` with an input string of `"Hello world!"`;
 
-What effect does calling the `alert` function have?
+What effect does calling the `alert` function have? It opens a popup message box in the browser with the text:
+You must click "OK" to dismiss it before you can do anything else on the page.
 
 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? It opens a popup input box asking:
+What is your name?
+and I can enter a response, then click "OK" or "Cancel".
+
+What is the return value of `prompt`? Return value:
+
+If I enter a name (e.g., "Sami") and press OK, it returns the string: "Sami"
+
+If I press Cancel, it returns: null

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

@@ -4,13 +4,18 @@ 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?
+What output do you get? output: ƒ log() { [native code] }
 
-Now enter just `console` in the Console, what output do you get back?
+Now enter just `console` in the Console, what output do you get back?output: console {debug: ƒ, error: ƒ, info: ƒ, log: ƒ, warn: ƒ, …}
 
-Try also entering `typeof console`
+Try also entering `typeof console` output : object
 
 Answer the following questions:
 
-What does `console` store?
+What does `console` store? stores a collection of methods (functions) that are used to log information or debug JavaScript code.
+
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+
+This syntax uses dot notation. In JavaScript, the dot . is used to access a property or method of an object.
+
+console is the object.

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

@@ -1,5 +1,7 @@
 // Predict and explain first...
-//  =============> write your prediction here
+//  =============> // =============> write your prediction here
+//  I predict the code will throw an error because the variable `str` is being declared twice in the same function scope.
+
 
 // call the function capitalise with a string input
 // interpret the error message and figure out why an error is occurring
@@ -9,5 +11,17 @@ function capitalise(str) {
   return str;
 }
 
-// =============> write your explanation here
+// =============>  write your explanation here
+// The function already receives `str` as a parameter. 
+// Inside the function, it tries to declare `let str = ...`, 
+// which causes a conflict because JavaScript does not 
+// allow redeclaring the same variable name in the same scope using `let`. 
+// This leads to a `SyntaxError: Identifier 'str' has already been declared`.
+
+
 // =============> write your new code here
+// =============> write your new code here
+function capitalise(str) {
+  let capitalisedStr = `${str[0].toUpperCase()}${str.slice(1)}`;
+  return capitalisedStr;
+}

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

@@ -1,4 +1,9 @@
 // Predict and explain first...
+// =============> write your prediction here
+//   I predict this program will throw a `SyntaxError` because 
+// the parameter `decimalNumber` is being redeclared inside the function using `const`. 
+// Also, the variable `decimalNumber` is being accessed outside the function where it's not defined.
+
 
 // Why will an error occur when this program runs?
 // =============> write your prediction here
@@ -15,6 +20,20 @@ function convertToPercentage(decimalNumber) {
 console.log(decimalNumber);
 
 // =============> write your explanation here
+// The function already has a parameter named `decimalNumber`, 
+// but inside the function, it's trying to declare another 
+// constant with the same name: `const decimalNumber = 0.5;`. 
+// JavaScript doesn’t allow redeclaring a variable that already exists in the same scope.  
+// Also, `console.log(decimalNumber)` is outside the function and `decimalNumber` is not 
+// defined in the global scope, so that will cause a `ReferenceError`.
+
 
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+
+function convertToPercentage(decimalNumber) {
+  const percentage = `${decimalNumber * 100}%`;
+  return percentage;
+}
+
+console.log(convertToPercentage(0.5)); 

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

@@ -2,19 +2,32 @@
 // Predict and explain first BEFORE you run any code...
 
 // this function should square any number but instead we're going to get an error
+// The code will throw a **SyntaxError** because you cannot 
+// use a number (`3`) as a function parameter name.
 
 // =============> write your prediction of the error here
+// SyntaxError: Unexpected number
 
 function square(3) {
     return num * num;
 }
 
 // =============> write the error message here
+// SyntaxError: Unexpected number
 
 // =============> explain this error message here
+// In JavaScript, function parameters must be valid variable names (identifiers).  
+// Using a number like `3` directly as a parameter name is invalid syntax, 
+// so JavaScript throws a `SyntaxError: Unexpected number`.
 
 // Finally, correct the code to fix the problem
 
 // =============> write your new code here
 
+function square(num) {
+  return num * num;
+}
+
+console.log(square(3)); 
+
 

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

@@ -1,6 +1,10 @@
 // Predict and explain first...
 
 // =============> write your prediction here
+// I predict that the console will log `320` first (from inside the function), 
+// but then the message will say: "The result of multiplying 10 and 32 is undefined".
+
+// Explanation:
 
 function multiply(a, b) {
   console.log(a * b);
@@ -9,6 +13,16 @@ function multiply(a, b) {
 console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
 
 // =============> write your explanation here
+// The function `multiply` logs the result of `a * b`, but does not return it. 
+// When it's used inside a template literal, JavaScript evaluates `multiply(10, 32)` as `undefined`, 
+// because the function has no return value. That's why we get:  
+// `The result of multiplying 10 and 32 is undefined` — even though `320` is logged separately.
 
 // Finally, correct the code to fix the problem
 //  =============> write your new code here
+
+function multiply(a, b) {
+  return a * b;
+}
+
+console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);

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

@@ -1,13 +1,27 @@
 // Predict and explain first...
-//  =============> write your prediction here
 
+// =============> write your prediction here
+// I predict that this will print: "The sum of 10 and 32 is undefined"
+// because the function has a return statement with no value.
+
+// Explanation:
 function sum(a, b) {
   return;
   a + b;
+  // =============> write your explanation here
+  // The `return;` statement ends the function early, so `a + b` is never reached.
+  // In JavaScript, any code after a bare `return;` is ignored (unreachable code).
+  // That's why the function returns `undefined`, not the actual sum.
 }
 
 console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
 
-// =============> write your explanation here
 // Finally, correct the code to fix the problem
 //  =============> write your new code here
+function sum(a, b) {
+  return a + b;
+}
+
+console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
+// Now the function returns the correct result: 42
+

Sprint-2/2-mandatory-debug/2.js

@@ -2,7 +2,11 @@
 
 // Predict the output of the following code:
 // =============> Write your prediction here
+// I predict that all three log statements will output: "The last digit of 42 is 3", "105 is 3", "806 is 3"
+// Because the getLastDigit function doesn’t use the input — it always returns the last digit of the constant 
+// `num = 103`.
 
+// Original Code
 const num = 103;
 
 function getLastDigit() {
@@ -15,10 +19,25 @@ console.log(`The last digit of 806 is ${getLastDigit(806)}`);
 
 // Now run the code and compare the output to your prediction
 // =============> write the output here
+// The actual output is:
+// The last digit of 42 is 3
+// The last digit of 105 is 3
+// The last digit of 806 is 3
+
 // Explain why the output is the way it is
 // =============> write your explanation here
+// The function `getLastDigit` doesn't take any parameter, and it always uses the fixed variable `num = 103`.
+// So regardless of the input in the log statements, the function always returns the last digit of 103, which is "3".
+
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+function getLastDigit(number) {
+  return number.toString().slice(-1);
+}
+
+console.log(`The last digit of 42 is ${getLastDigit(42)}`);    // 2
+console.log(`The last digit of 105 is ${getLastDigit(105)}`);  // 5
+console.log(`The last digit of 806 is ${getLastDigit(806)}`);  // 6
+
+// Now the function works correctly by taking a number as input and returning its last digit.
 
-// This program should tell the user the last digit of each number.
-// Explain why getLastDigit is not working properly - correct the problem

Sprint-2/3-mandatory-implement/1-bmi.js

@@ -1,19 +1,13 @@
-// Below are the steps for how BMI is calculated
-
-// The BMI calculation divides an adult's weight in kilograms (kg) by their height in metres (m) squared.
-
-// For example, if you weigh 70kg (around 11 stone) and are 1.73m (around 5 feet 8 inches) tall, you work out your BMI by:
-
-// squaring your height: 1.73 x 1.73 = 2.99
-// dividing 70 by 2.99 = 23.41
-// Your result will be displayed to 1 decimal place, for example 23.4.
+function calculateBMI(weight, height) {
+  // Square the height (height in meters)
+  const heightSquared = height * height;
 
-// You will need to implement a function that calculates the BMI of someone based off their weight and height
+  // Divide weight by height squared to get BMI
+  const bmi = weight / heightSquared;
 
-// Given someone's weight in kg and height in metres
-// Then when we call this function with the weight and height
-// It should return their Body Mass Index to 1 decimal place
+  // Return the BMI rounded to 1 decimal place
+  return bmi.toFixed(1); // toFixed returns a string, which is fine unless you need it as a number
+}
 
-function calculateBMI(weight, height) {
-    // return the BMI of someone based off their weight and height
-}
+// Example usage:
+console.log(calculateBMI(70, 1.73)); // Output: "23.4"