London | 25-ITP-Sep | Adnaan Abo | Sprint 2 | Coursework/sprint 2

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

@@ -1,13 +1,29 @@
 // Predict and explain first...
 //  =============> write your prediction here
+// the code will throw an error because the variable str is being declared twice within the same scope
 
 // call the function capitalise with a string input
 // interpret the error message and figure out why an error is occurring
 
+/*
 function capitalise(str) {
   let str = `${str[0].toUpperCase()}${str.slice(1)}`;
   return str;
 }
 
-// =============> write your explanation here
-// =============> write your new code here
+*/
+
+// =============> write your explanation 
+/* the code throws a SyntaxError because the variable 'str' is declared twice in the same scope using 'let'. In JavaScript, 
+ you cannot declare a variable with the same name more than once in the same scope. The first declaration of 'str' is as a 
+ function parameter, and the second declaration is within the function body. To fix this, you can either rename the second 
+ 'str' variable or remove the 'let' keyword from the second declaration to reassign the value to the existing parameter variable.*/
+
+ // =============> write your new code here
+
+function capitalise(str) {
+  str = `${str[0].toUpperCase()}${str.slice(1)}`;
+  return str;
+}
+
+console.log(capitalise("hello")); // Output: "Hello"

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

@@ -2,9 +2,12 @@
 
 // Why will an error occur when this program runs?
 // =============> write your prediction here
+// the code will throw an error because the variable str is being declared twice within the same scope
 
 // Try playing computer with the example to work out what is going on
 
+/*
+
 function convertToPercentage(decimalNumber) {
   const decimalNumber = 0.5;
   const percentage = `${decimalNumber * 100}%`;
@@ -14,7 +17,23 @@ function convertToPercentage(decimalNumber) {
 
 console.log(decimalNumber);
 
+*/
+
 // =============> write your explanation here
+/* The error occurs because the variable 'decimalNumber' is declared twice within the same function scope using 'const'. 
+This is not allowed in JavaScript, as each variable must have a unique name within its scope. When the function is called, 
+the JavaScript engine encounters the second declaration of 'decimalNumber' and throws a SyntaxError indicating that the 
+identifier has already been declared.*/
 
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+
+let decimalNumber = 0.6;
+
+function convertToPercentage(decimalNumber) {
+  const percentage = `${decimalNumber * 100}%`;
+
+  return percentage;
+}
+
+console.log(convertToPercentage(decimalNumber));

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

@@ -4,17 +4,37 @@
 // this function should square any number but instead we're going to get an error
 
 // =============> write your prediction of the error here
+/* I predict that the code will throw a SyntaxError because the parameter '3' is not a valid identifier. 
+Function parameters must be valid variable names.*/
+
+/*
 
 function square(3) {
     return num * num;
 }
 
+*/
+
 // =============> write the error message here
+/* Process exited with code 1
+Uncaught SyntaxError /home/ads/Desktop/CYF-SEP/Module-Structuring-and-Testing-Data/Sprint-2/1-key-errors/2.js:10
+function square(3) {
+                ^
+
+SyntaxError: Unexpected number */
 
 // =============> explain this error message here
+/* The error message indicates a SyntaxError due to an "Unexpected number". This occurs because the function
+parameter '3' is not a valid identifier. In JavaScript, function parameters must be valid variable names, and 
+using a number as a parameter name is not allowed. The JavaScript engine expects a valid identifier after the 
+opening parenthesis of the function declaration, but it encounters a number instead, leading to the syntax error.*/
 
 // Finally, correct the code to fix the problem
 
 // =============> write your new code here
 
+function square(num) {
+    return num * num;
+}
 
+console.log(square(4)); // Output: 16

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

@@ -1,14 +1,26 @@
 // Predict and explain first...
 
 // =============> write your prediction here
+/* The function multiply does not return any value, it only logs the product of a and b to the console. 
+Therefore, when we try to log the result of multiply(10, 32), it will log 'undefined' because the 
+function does not return anything.*/
 
+/*
 function multiply(a, b) {
   console.log(a * b);
 }
 
 console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
+*/
 
 // =============> write your explanation here
+// The function multiply does not have a return statement, so it returns undefined by default.
 
 // 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
+// An error will occur because the function 'sum' has a return statement that is not returning any value.
 
+/*
 function sum(a, b) {
   return;
   a + b;
 }
 
 console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
+*/
 
 // =============> write your explanation here
+/* The error occurs because the 'sum' function has a return statement that does not return any value. In JavaScript, 
+when a function reaches a return statement without a value, it returns 'undefined' by default. Therefore, when we 
+call 'sum(10, 32)', it returns 'undefined', and the output will be "The sum of 10 and 32 is undefined". To fix this, 
+we need to ensure that the function returns the result of 'a + b'.*/
+
 // 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

@@ -2,7 +2,10 @@
 
 // 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", and "The last digit of 806 is 3" because 
+the function getLastDigit always returns the last digit of the constant number 'num', which is set to 103.*/
 
+/*
 const num = 103;
 
 function getLastDigit() {
@@ -12,13 +15,34 @@ function getLastDigit() {
 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)}`);
+*/
 
 // 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
-// Finally, correct the code to fix the problem
-// =============> write your new code here
+/* The output is the way it is because the function getLastDigit does not use its parameter. Instead, it always
+returns the last digit of the constant variable 'num', which is set to 103. Therefore, regardless of the input 
+value provided when calling getLastDigit, it will always return '3', the last digit of 103. To fix this, we need 
+to modify the function to accept a parameter and return the last digit of that parameter.*/
 
 // This program should tell the user the last digit of each number.
 // Explain why getLastDigit is not working properly - correct the problem
+// the return function is not using the parameter passed to it and is instead using a constant value
+
+
+// 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)}`);
+console.log(`The last digit of 105 is ${getLastDigit(105)}`);
+console.log(`The last digit of 806 is ${getLastDigit(806)}`);
+

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

@@ -14,6 +14,13 @@
 // Then when we call this function with the weight and height
 // It should return their Body Mass Index to 1 decimal place
 
+let weight = 80; // in kg
+let height = 1.73; // in metres
+
 function calculateBMI(weight, height) {
     // return the BMI of someone based off their weight and height
-}
+    let bmi = weight / (height * height);
+    return bmi;
+}
+
+console.log(calculateBMI(weight, height).toFixed(1)); // should return 26.7

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

@@ -14,3 +14,14 @@
 // 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
+
+const input1 = "hello there";
+const input2 = "lord of the rings";
+
+function toUpperSnakeCase(str) {
+    // return the string in UPPER_SNAKE_CASE
+    return str.replace(/ /g, "_").toUpperCase();  // Replace spaces with underscores and convert to uppercase
+}
+
+console.log(toUpperSnakeCase(input1)); // should return "HELLO_THERE"
+console.log(toUpperSnakeCase(input2)); // should return "LORD_OF_THE_RINGS"

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

@@ -4,3 +4,28 @@
 // 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 // to remove the trailing 'p'
+);
+
+const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+const pounds = paddedPenceNumberString.substring(
+  0,
+  paddedPenceNumberString.length - 2 // all but the last two characters
+);
+
+const pence = paddedPenceNumberString
+  .substring(paddedPenceNumberString.length - 2)  // the last two characters
+  .padEnd(2, "0");  // in case there is only one character of pence
+
+return `£${pounds}.${pence}`;
+}
+
+console.log(toPounds("399p")); // should log "£3.99"
+console.log(toPounds("5p")); // should log "£0.05"
+console.log(toPounds("89p")); // should log "£0.89"
+console.log(toPounds("123456p")); // should log "£1234.56"

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

@@ -18,17 +18,24 @@ function formatTimeDisplay(seconds) {
 
 // a) When formatTimeDisplay is called how many times will pad be called?
 // =============> write your answer here
+// pad is called 3 times because there are 3 values to be padded - hours, minutes and seconds
 
 // Call formatTimeDisplay with an input of 61, now answer the following:
+console.log(formatTimeDisplay(61)); // Should return "00:01:01"
 
 // b) What is the value assigned to num when pad is called for the first time?
 // =============> write your answer here
+// num is assigned the value of totalHours which is 0 because 61 seconds is less than a minute
 
 // c) What is the return value of pad is called for the first time?
 // =============> write your answer here
+// The return value is "00" because the padStart method adds a "0" to the start of the string "0" to make it 2 characters long
 
 // 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
+// num is assigned the value of remainingSeconds which is 1 because 61 seconds is 1 second more than a full minute (60 seconds)
 
 // 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
+// The return value is "01" because the padStart method adds a "0" to the start of the string "1" to make it 2 characters long
+