I have dome sprint2 for structuring data module

Author: Alrzini2025

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

@@ -4,3 +4,4 @@ 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
+// updates the value of the variable count by adding 1

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

@@ -1,13 +1,13 @@
 // Predict and explain first...
-//  =============> write your prediction here
+//  Missing backticks for template string template strings need to use backticks `, but here ${} is used without them
 
-// call the function capitalise with a string input
+// call the function capitalise with a string input (error)
 // interpret the error message and figure out why an error is occurring
+// ${} must be inside backticks and str is being redeclared (it is already the function parameter) 
 
-function capitalise(str) {
-  let str = `${str[0].toUpperCase()}${str.slice(1)}`;
-  return str;
-}
 
 // =============> write your explanation here
-// =============> write your new code here
+// =============> This function takes a string and returns a new string with the first letter  in capital
+function capitalise(str) {
+  return `${str[0].toUpperCase()}${str.slice(1)}`;
+} 

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

@@ -1,20 +1,15 @@
 // Predict and explain first...
 
-// Why will an error occur when this program runs?
-// =============> write your prediction here
+// decimalNumber is already declared as a function parameter. and name variable the same 
 
 // Try playing computer with the example to work out what is going on
 
 function convertToPercentage(decimalNumber) {
-  const decimalNumber = 0.5;
   const percentage = `${decimalNumber * 100}%`;
-
   return percentage;
 }
 
-console.log(decimalNumber);
-
-// =============> write your explanation here
+console.log(convertToPercentage(0.5)); 
 
-// Finally, correct the code to fix the problem
-// =============> write your new code here
+// creates a function named convertToPercentage
+// The function returns the percentage string.SS

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

@@ -3,18 +3,27 @@
 
 // this function should square any number but instead we're going to get an error
 
-// =============> write your prediction of the error here
+// Error because the variable 'num' is not defined when we try to call the function. 
+// The function expects 
+// a parameter but we're not passing any argument when calling it.
 
-function square(3) {
+function square(num) {
     return num * num;
 }
 
-// =============> write the error message here
+// The function will return NaN  (Not a Number) 
+//  this doesn't throw an error, but returns NaN  because: 
+// - num is undefined (no argument passed) 
+// - undefined * undefined = NaN 
 
-// =============> explain this error message here
+// When square() is called without an argument, the parameter 'num' has 
+// // the value 'undefined'. When you multiply undefined * undefined, 
+// // JavaScript returns NaN (Not a Number) instead of throwing an error. 
 
-// Finally, correct the code to fix the problem
-
-// =============> write your new code here
+function square(num)
+ {
+     return num * num;
+     } 
+     console.log(square(5)); // Output: 25 console.log(square(10)); 
 
 

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

@@ -1,6 +1,10 @@
 // Predict and explain first...
 
-// =============> write your prediction here
+//The output  is 320
+//no define the reult of multiplying 10 and 32
+// This is because the multiply function uses console.log() instead of return.
+// The function will print 320 to the console, but then will show 
+// "undefined" because the function doesn't return a value.
 
 function multiply(a, b) {
   console.log(a * b);
@@ -10,5 +14,21 @@ console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
 
 // =============> write your explanation here
 
+//The multiply() function calculates a * b (which is 320) and prints it
+// using console.log(). 
+//console.log() doesn't return a value  just output of console
+// it only displays output to the console.
+//
+// there is no return statement, it  returns 'undefined'. 
+// the function:
+// 1. Prints "320" to the console
+// 2. Returns undefined
+//    "The result of multiplying 10 and 32 is undefined"
+
 // Finally, correct the code to fix the problem
 //  =============> write your new code here
+
+function multiply(a, b) {
+  return a * b;        // use return not console 
+}
+console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);

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

@@ -1,6 +1,12 @@
 // Predict and explain first...
 //  =============> write your prediction here
 
+//The output will be:
+// "The sum of 10 and 32 is not defined because the return statement without a value.
+// The line "a + b;"  after return will not executed
+// return undefined. The code after return is unreachable.
+
+
 function sum(a, b) {
   return;
   a + b;
@@ -9,5 +15,19 @@ function sum(a, b) {
 console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
 
 // =============> write your explanation here
+//   a + b;         ← This line will not executes (unreachable code)
+// So the function effectively becomes:
+//   function sum(a, b) {
+//     return undefined;
+//     a + b;  // not execute
+//   }
+// The return statement immediately exits the function and returns undefined.
+// Any code after a return statement is "unreachable" and not execute.
+// result is the sum of 10 and 32 is undefined"
 // 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)}`);

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

@@ -2,6 +2,13 @@
 
 // Predict the output of the following code:
 // =============> Write your prediction here
+//The output will be:
+// The last digit of 42 is 3
+// The last digit of 105 is 3
+// The last digit of 806 is 3
+//
+// All  outputs show "3" because the function not taking the parameter
+// passe value to  'num' (which is 103), so it returns the last digit of 103, which is 3.
 
 const num = 103;
 
@@ -15,10 +22,34 @@ 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 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() has TWO problems:
+// The function definition doesn't have a parameter,
+// it can't receive the values (42, 105, 806) added to it.
+//inside the function, it uses the global constant
+// 'num' (which is 103) instead of using the parameter 
+//getLastDigit(42) call  function not taking 42
+//  num (103) converts to "103"
+// -slice(-1) gets the last character  "3"
+// returns "3" 
 // Finally, correct the code to fix the problem
 // =============> write your new code here
 
+const num1 = 103;
+function getLastDigit(number) {  // Added parameter 'number'
+  return number.toString().slice(-1);  // Use 'number' instead of 'num'
+}
+console.log(`The last digit of 42 is ${getLastDigit(42)}`);
+console.log(`The last digit of 105 is ${getLastDigit(105)}`);
+console.log(`The last digit of 806 is ${getLastDigit(806)}`);
+
 // This program should tell the user the last digit of each number.
 // Explain why getLastDigit is not working properly - correct the problem
+//The function has no parameter when call getLastDigit(42), 
+// the number 42 is passed but storage variable to save it.
+//  The function can't use it because it doesn't have a parameter to receive it.

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

@@ -16,4 +16,7 @@
 
 function calculateBMI(weight, height) {
     // return the BMI of someone based off their weight and height
-}
+      return Math.round((weight / (height * height)) * 10) / 10;
+}
+
+console.log(calculateBMI(70, 1.73));  

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

@@ -14,3 +14,19 @@
 // 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
+
+function toUpperSnakeCase(str) {
+    // Step 1: Replace all spaces with _
+    const withUnderscores = str.replace(/ /g, '_');
+   
+    // Step 2: Convert to uppercase
+    const upperCase = withUnderscores.toUpperCase();
+   
+    return upperCase;
+}
+
+// Test 
+console.log(toUpperSnakeCase("hello there"));           // "HELLO_THERE"
+console.log(toUpperSnakeCase("lord of the rings"));     // "LORD_OF_THE_RINGS"
+console.log(toUpperSnakeCase("the quick brown fox"));   // "THE_QUICK_BROWN_FOX"
+console.log(toUpperSnakeCase("code your future"));      // "CODE_YOUR_FUTURE"

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

@@ -4,3 +4,32 @@
 // 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 to convert pence string to pounds format
+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}`;
+}
+
+// Test the function with inputs
+console.log(toPounds("399p"));    // "£3.99"
+console.log(toPounds("50p"));     // "£0.50"
+console.log(toPounds("5p"));      // "£0.05"
+console.log(toPounds("1p"));      // "£0.01"
+console.log(toPounds("99p"));     // "£0.99"
+console.log(toPounds("100p"));    // "£1.00"
+console.log(toPounds("1250p"));   // "£12.50"
+console.log(toPounds("10000p"));  // "£100.00"
+console.log(toPounds("199p"));    // "£1.99"
+console.log(toPounds("2550p"));   // "£25.50"