London | ITP-May-2025 | Seddiq Azam | Module-Structuring-and-Testing-Data | Sprint-2

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

@@ -10,4 +10,16 @@ function capitalise(str) {
 }
 
 // =============> write your explanation here
+
+//   Looking at the function declaration, it shows that str is already a parameter and has already been declared. 
+//   let cannot declare a new variable in the same scope. Therefore, a syntax error occurs. 
+
+
 // =============> write your new code here
+
+// We need to remove let from the function declaration so we can modify the value of the existing str variable 
+
+function capitalise(str) {
+  str = `${str[0].toUpperCase()}${str.slice(1)}`;
+  return str;
+}

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

@@ -16,5 +16,25 @@ console.log(decimalNumber);
 
 // =============> write your explanation here
 
+// In this function declaration, we can see that `decimalNumber` is already a parameter of the function.
+// We cannot redeclare the same variable name in the same scope using `const` or `let`.
+
+// When I originally called `console.log(decimalNumber);` outside the function,
+// It printed the value `0.5` because `decimalNumber` was declared in the global scope.
+
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+
+// Corrected Code:
+// To fix the issue, we define the value of `decimalNumber` outside the function and pass it in.
+// This ensures the variable exists in the global scope and avoids redeclaring it inside the function.
+// We also change the console log to call the function properly.
+
+const decimalNumber = 0.5;
+
+function convertToPercentage(decimalNumber) {
+  const percentage = `${decimalNumber * 100}%`;
+  return percentage;
+}
+
+console.log(convertToPercentage(decimalNumber));  // Output: "50%"

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

@@ -11,10 +11,34 @@ function square(3) {
 
 // =============> write the error message here
 
+Uncaught SyntaxError: Unexpected number     
+    return num * num;
+    return num * num;
+    ^^^^^^
+
+Uncaught SyntaxError: Illegal return statement
+
+
 // =============> explain this error message here
 
+// The error states that there is an unexpected number. This means the parameter is invalid.
+// We cannot use a number as a parameter name. Function parameters must be valid variable names.
+
+// In the return statement, we used 'num', but it was never defined. 
+// Since 'num' is not declared as a parameter, this causes a ReferenceError.
+
 // Finally, correct the code to fix the problem
 
-// =============> write your new code here
+// To fix the code:
+// We need to change the parameter from the number 3 to a proper variable name, such as 'num'.
+// This allows the function 'square' to define and use 'num' correctly as the input.
+// We also need to pass a value (like 3) to the function when calling it inside console.log, 
+// so it prints the correct result.
 
 
+// =============> write your new code here
+
+function square(num) {
+  return num * num;
+}
+console.log(square(3));  // Output: 9

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

@@ -10,5 +10,26 @@ console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
 
 // =============> write your explanation here
 
-// Finally, correct the code to fix the problem
+// I can see that the function does not return a value; it only logs the result.
+// Inside the function call multiply(10, 32), a = 10 and b = 32.
+// It runs console.log(a * b), which simply logs 320 to the console but does not return anything.
+// When a function doesn't explicitly return a value, it returns undefined by default.
+// Therefore, the result of multiplying 10 and 32 is undefined when used inside the template string.
+// The console output will be:
+320
+The result of multiplying 10 and 32 is undefined
+
+
 //  =============> write your new code here
+
+// The original function only logged the result using console.log and did not return a value.
+// As a result, using it inside a template string would return 'undefined'.
+// To fix this, we add a return statement so that the function returns the result of the multiplication.
+
+function multiply(a, b) {
+  return a * b;
+}
+
+// Now the function returns the result, and it can be correctly used inside the template literal.
+
+console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);

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

@@ -9,5 +9,20 @@ function sum(a, b) {
 console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
 
 // =============> write your explanation here
+
+// I can see that there is a semicolon after the function return. This tells JavaScript that the function stops there. Any line of codes after that will be ignored.
+
+
 // Finally, correct the code to fix the problem
+
+//We need to remove the semicolon so the function can continue to the following line. 
+
+
+
 //  =============> write your new code here
+
+function sum(a, b) {
+  return a + b;
+}
+
+console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);

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

@@ -3,6 +3,9 @@
 // Predict the output of the following code:
 // =============> Write your prediction here
 
+// I can see from the function call that num is defined as a fixed number, which is 103.
+// So the function num.toString() will use 103 for num always, no matter what number is entered as a parameter. 
+
 const num = 103;
 
 function getLastDigit() {
@@ -14,11 +17,55 @@ console.log(`The last digit of 105 is ${getLastDigit(105)}`);
 console.log(`The last digit of 806 is ${getLastDigit(806)}`);
 
 // Now run the code and compare the output to your prediction
+
+// Done.
+// It does exactly what I expected. Whatever number you pass into getLastDigit as an argument, it still returns 3.
+
 // =============> write the output here
+
+console.log(`The last digit of 42 is ${getLastDigit(42)}`);
+The last digit of 42 is 3
+
+console.log(`The last digit of 105 is ${getLastDigit(105)}`);
+The last digit of 105 is 3
+
+console.log(`The last digit of 806 is ${getLastDigit(806)}`);
+The last digit of 806 is 3
+
 // Explain why the output is the way it is
 // =============> write your explanation here
+
+// The function getLastDigit does not accept any arguments.
+// A global variable, num, is already set to 103. 
+// So the function always uses this value instead of the numbers passed in.
+// Here's what happens:
+103.toString() = "103"
+"103".slice(-1) = "3"
+
+
 // Finally, correct the code to fix the problem
+
+// We need to assign a parameter to the function getLastDigit(), which we will call "number".
+// Inside the function, it converts "number" to a string and gets the last character using .slice(-1).
+
 // =============> 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"
+
+//Output
+
+The last digit of 42 is 2
+The last digit of 105 is 5
+The last digit of 806 is 6
+
 // This program should tell the user the last digit of each number.
 // Explain why getLastDigit is not working properly - correct the problem
+
+// The function getLastDigit doesn't accept any parameters; it works with the variable num, which is fixed as 103.
+// No matter what number is entered into getLastDigit, it ignores it and returns the last digit of 103 every time.

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

@@ -16,4 +16,44 @@
 
 function calculateBMI(weight, height) {
     // return the BMI of someone based off their weight and height
-}
+}
+
+// Answer:
+
+// BMI is calculated as weight divided by height squared:
+// BMI = weight / (height * height)
+
+// First, we create a variable to store the BMI value:
+const bmi = weight / (height * height);
+
+// To format the result to 1 decimal place, we use the .toFixed(1) method.
+// This converts the number to a string rounded to one decimal place:
+// bmi.toFixed(1)
+
+// Since .toFixed() returns a string, we convert it back to a number
+// using parseFloat so we can use the result in further arithmetic operations.
+
+// We can define the function as follows:
+
+function calculateBMI(weight, height) {
+    const bmi = weight / (height * height);
+    return parseFloat(bmi.toFixed(1));
+}
+
+// What we will enter:
+function calculateBMI(70, 1.73) {
+    const bmi = 70 / (1.73 * 1.73);
+    return parseFloat(bmi.toFixed(1));
+}
+console.log(`The BMI for a weight of 70kg and height of 1.73m is ${calculateBMI(70, 1.73)}`);
+
+// The results: 
+
+// The BMI for a weight of 70kg and height of 1.73m is 23.4
+
+
+//    Weight = 70 kg, height = 1.73 m.
+//    	•	BMI = 70 ÷ (1.73 × 1.73) = 70 ÷ 2.9929 ≈ 23.41
+//    	•	Rounded to 1 decimal = 23.4
+//    	•	The function returns 23.4
+

Sprint-2/3-mandatory-implement/2-cases.js

@@ -14,3 +14,26 @@
 // You will need to come up with an appropriate name for the function
 // Use the MDN string documentation to help you find a solution
 // This might help https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/toUpperCase
+
+// Answer:
+
+// Requirements:
+// 1. Replace spaces with underscores (_)
+// 2. Convert all letters to uppercase
+
+// We will call the function toUpperSnakeCase().
+// We'll use the .replace() method to replace all spaces with underscores.
+// We'll use .toUpperCase() to convert all letters to uppercase.
+// The /g flag in the regular expression ensures that all spaces in the string are matched and replaced,
+// not just the first one. Without /g, only the first space would be replaced.
+
+
+function toUpperSnakeCase(str) {
+  return str.replace(/ /g, '_').toUpperCase();
+}
+
+// Example usage:
+
+console.log(toUpperSnakeCase("hello there"));           // Output: "HELLO_THERE"
+console.log(toUpperSnakeCase("lord of the rings"));     // Output: "LORD_OF_THE_RINGS"
+console.log(toUpperSnakeCase("all upper case"));        // Output: "ALL_UPPER_CASE"

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

@@ -4,3 +4,36 @@
 // You will need to declare a function called toPounds with an appropriately named parameter.
 
 // You should call this function a number of times to check it works for different inputs
+
+
+function toPounds(penceString) {
+  const penceStringWithoutTrailingP = penceString.substring(0, penceString.length - 1);
+
+  const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+
+  const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2);
+
+  const pence = paddedPenceNumberString
+    .substring(paddedPenceNumberString.length - 2)
+    .padEnd(2, "0");
+
+  return `£${pounds}.${pence}`;
+}
+
+
+console.log(toPounds("399p"));   // Output: £3.99
+console.log(toPounds("9p"));     // Output: £0.09
+console.log(toPounds("75p"));    // Output: £0.75
+console.log(toPounds("1234p"));  // Output: £12.34
+
+
+... }console.log(toPounds("399p"));
+£3.99
+undefined
+> console.log(toPounds("9p")); 
+£0.09
+undefined
+> console.log(toPounds("1234p"));
+£12.34
+undefined
+> 

Sprint-2/4-mandatory-interpret/time-format.js

@@ -19,16 +19,51 @@ function formatTimeDisplay(seconds) {
 // a) When formatTimeDisplay is called how many times will pad be called?
 // =============> write your answer here
 
+// `${pad(totalHours)}:${pad(remainingMinutes)}:${pad(remainingSeconds)}`
+//  pad is called three times 
+// pad(totalHours)
+// pad(remainingMinutes)
+// pad(remainingSeconds)
+
 // Call formatTimeDisplay with an input of 61, now answer the following:
 
 // b) What is the value assigned to num when pad is called for the first time?
 // =============> write your answer here
 
+// The first call is: ${pad(totalHours)}
+// totalHours = (1 - 1) / 60 = 0 / 60 = 0
+// So, pad(totalHours) becomes pad(0)
+// Therefore, the value assigned to num is 0
+
 // c) What is the return value of pad is called for the first time?
 // =============> write your answer here
 
+// pad(0) is called
+// inside the function:
+// num = 0
+// num.toString() = "0"
+// "0".padStart(2, "0") means make the string at least two characters long. 
+// if it is shorter, add "0" at the beginning. 
+// Since "0" is one character long, a "0" is added → "00"
+// So, the return value is "00"
+
 // d) What is the value assigned to num when pad is called for the last time in this program?  Explain your answer
 // =============> write your answer here
 
+//  The last call is for seconds: pad(remainingSeconds)
+//  remainingSeconds = 61 % 60 = 1, so the function call is pad(1)
+//  Inside this call:
+//  num = 1
+//  num.toString() = "1"
+//  "1".padStart(2, "0") = "01"
+//  Therefore, the value assigned to num is 1
+
+
 // e) What is the return value assigned to num when pad is called for the last time in this program?  Explain your answer
 // =============> write your answer here
+
+//  remainingSeconds = 1
+//  pad(1) converts 1 into the string "1"
+//  Then it pads it to two digits with "0" in front → "01"
+//  This makes sure time values are always two digits like "01", "09", "12", etc., which is standard in time formatting (HH:MM:SS).
+// So, the return value is "01"