Birmingham | 26-ITP-May | Ogbemi Mene | Sprint 2 | coursework

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

@@ -1,13 +1,30 @@
 // Predict and explain first...
-//  =============> write your prediction here
+// If you try to run this code, it will throw a SyntaxError: Identifier 'str' has already been declared.
 
 // 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;
+    let str = `${str[0].toUpperCase()}${str.slice(1)}`;
+
+    return str; 
 }
+// When you define function capitalise(str), JavaScript automatically creates a local variable named str inside the function's scope, 
+// assigning it whatever value you pass into the function.
+// The let keyword has a strict rule: you cannot declare a variable that already exists in the same scope. 
+// Because str was already claimed by the function's parameter, JavaScript immediately stops and throws a SyntaxError before it even tries to capitalize anything.
+// this is the reason why the error is occurring.
+// the if condition i added is to ensure that if an empty string is passed to the function, it will return the empty string instead of throwing an error.
+// To fix the error, you can simply remove the let keyword and just assign the new value to str without redeclaring it.
+
+function capitalise(str) {
+  if (typeof str !== "string") {
+    return str;
+  }
+
+    return `${str[0].toUpperCase()}${str.slice(1)}`;
+
+}
+console.log(capitalise("hello world!"));
+
 
-// =============> write your explanation here
-// =============> write your new code here

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

@@ -1,7 +1,7 @@
 // Predict and explain first...
 
 // Why will an error occur when this program runs?
-// =============> write your prediction here
+// this will throw a SyntaxError: Identifier 'decimalNumber' has already been declared.
 
 // Try playing computer with the example to work out what is going on
 
@@ -14,7 +14,17 @@ function convertToPercentage(decimalNumber) {
 
 console.log(decimalNumber);
 
-// =============> write your explanation here
+// it will throw this error SyntaxError: Identifier 'decimalNumber' has already been declared.
+// by declaring the variable decimalNumber as a parameter inside the function parentheses. 
+// This will create it again on the next line using const, JavaScript gets confused and blocks the code from running.
 
 // Finally, correct the code to fix the problem
-// =============> write your new code here
+// this is the correct code below
+
+function convertToPercentage(decimalNumber) {
+  const percentage = `${decimalNumber * 100}%`;
+
+  return percentage;
+}
+
+console.log(convertToPercentage(0.5));

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

@@ -3,18 +3,21 @@
 
 // this function should square any number but instead we're going to get an error
 
-// =============> write your prediction of the error here
+// Variable and parameter names must be identifiers (like words, e.g., num, x, myNumber).
+//They cannot be literal values or specific numbers like 3.
 
 function square(3) {
-    return num * num;
+    //return num * num;
 }
 
-// =============> write the error message here
+// the error message is: SyntaxError: Unexpected number. 
 
-// =============> explain this error message here
+// The error message SyntaxError: Unexpected number means that JavaScript encountered a raw number,
+// where it was strictly expecting to see a variable name.
 
 // 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

@@ -1,14 +1,22 @@
 // Predict and explain first...
 
-// =============> write your prediction here
+// This code will actually run without throwing a red crash error, 
+// but it will print something very strange. the result of multiplying 10 and 32 is undefined.
 
 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
+// console.log() inside the function: Inside the multiply function, you used console.log(a * b). 
+// This instantly prints 320 to the screen, but it does not give that number back to the code that called it.
+//The Missing return: In JavaScript, if a function does not explicitly use the word return, it automatically hands back undefined.
+//The undefined string: Because multiply(10, 32) returns undefined, your outer console.log plugs undefined into the sentence, resulting in: "The result of multiplying 10 and 32 is undefined".
 
-// Finally, correct the code to fix the problem
-//  =============> write your new code here
+// Finally, correct the code to fix the problem  
+function multiply(a, b) {
+  return a * b;
+}
+
+console.log(multiply(10, 32));

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

@@ -1,5 +1,7 @@
 // Predict and explain first...
-//  =============> write your prediction here
+// This code will run without throwing a crash error, but it will print an incorrect result. 
+// The output will be:This code will run without throwing a crash error, but it will print an incorrect result. 
+// The output will be: The sum of 10 and 32 is undefined
 
 function sum(a, b) {
   return;
@@ -8,6 +10,13 @@ function sum(a, b) {
 
 console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
 
-// =============> write your explanation here
+// =============> the explanation:
+// The function sum has a return statement before the addition operation, which causes the function to return undefined immediately. 
+// To fix this, the return statement should be placed after the addition operation.
+// because the function is not a string i have to remove the backticks and use a normal string concatenation to print the result correctly.
 // Finally, correct the code to fix the problem
 //  =============> write your new code here
+function sum(a, b) {
+  return a + b;
+}
+console.log(sum(10, 32));

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

@@ -1,11 +1,12 @@
 // Predict and explain first...
 
 // Predict the output of the following code:
-// =============> Write your prediction here
+// this code might not run properly because the function getLastDigit is not set up to take any parameters,
+//  but we are trying to pass in a number when we call it.
 
-const num = 103;
+//const num = 103;
 
-function getLastDigit() {
+function getLastDigit(num) {
   return num.toString().slice(-1);
 }
 
@@ -14,11 +15,29 @@ 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
+// The output is the way it is because the function getLastDigit does not take any parameters, 
+// but we are trying to pass in a number when we call it. Instead, the function is using the variable num which is set to 103. 
+// Therefore, regardless of what number we pass in, the function will always return the last digit of 103, which is 3.
+
 // Finally, correct the code to fix the problem
-// =============> write your new code here
+
+const num = 103;
+
+function getLastDigit(num) {
+  return num.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)}`);
 
 // 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 is not working properly because it does not take any parameters,
+// to fix the problem, we need to add a parameter to the function definition so that it can accept a number when called.

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

@@ -15,5 +15,7 @@
 // It should return their Body Mass Index to 1 decimal place
 
 function calculateBMI(weight, height) {
-    // return the BMI of someone based off their weight and height
-}
+    const bmi = weight / (height * height);
+    return bmi.toFixed(1);
+}
+console.log(calculateBMI(70, 1.73)); 

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

@@ -14,3 +14,8 @@
 // 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) {
+  return str.toUpperCase().replace(/ /g, '_');
+}
+console.log(toUpperSnakeCase("lord of the rings"));

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

@@ -4,3 +4,27 @@
 // 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"));  
+console.log(toPounds("1250p"));  
+console.log(toPounds("5p"));    
+console.log(toPounds("70p"));
+console.log(toPounds("0p"));

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

@@ -21,18 +21,25 @@ function formatTimeDisplay(seconds) {
 // Questions
 
 // a) When formatTimeDisplay is called how many times will pad be called?
-// =============> write your answer here
+// pad will be called 3 times. Inside the return statement of formatTimeDisplay, 
+// pad is called once for totalHours, once for remainingMinutes, and once for 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
+// Answer: 0. Reason: The first evaluation in the template literal is pad(totalHours). 
+// Since totalHours is 0, 0 is passed as the argument to num.
 
 // c) What is the return value of pad is called for the first time?
-// =============> write your answer here
+// answer: "00". Reason: The while loop in pad checks if the length of numString is less than 2.
+// Since numString is "0", the loop runs and adds a "0" to the front, making it "00". 
+// The loop then checks again, and since the length is now 2, it exits and returns "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
+// Answer: 1. Reason: The last evaluation in the template literal is pad(remainingSeconds). 
+// Since remainingSeconds is 1, 1 is passed as the argument to num.
 
 // e) What is the return value of pad when it is called for the last time in this program?  Explain your answer
-// =============> write your answer here
+// Answer: "01". Reason: The while loop in pad checks if the length of numString is less than 2.
+// Since numString is "1", the loop runs and adds a "0" to the front, making it "01". 
+// The loop then checks again, and since the length is now 2, it exits and returns "01".

Sprint-2/5-stretch-extend/format-time.js

@@ -4,12 +4,20 @@
 
 function formatAs12HourClock(time) {
   const hours = Number(time.slice(0, 2));
+  const minutes = time.slice(3, 5);
+
   if (hours > 12) {
-    return `${hours - 12}:00 pm`;
+    const convertedHours = hours - 12;
+    // Pad the hour with a leading zero if it's a single digit (e.g., 3 becomes "03")
+    const paddedHours = String(convertedHours).padStart(2, "0");
+    return `${paddedHours}:${minutes} pm`;
   }
+
   return `${time} am`;
 }
 
+// === Your Tests (All will now pass silently!) ===
+
 const currentOutput = formatAs12HourClock("08:00");
 const targetOutput = "08:00 am";
 console.assert(
@@ -23,3 +31,11 @@ console.assert(
   currentOutput2 === targetOutput2,
   `current output: ${currentOutput2}, target output: ${targetOutput2}`
 );
+
+console.assert(formatAs12HourClock("15:00") === "03:00 pm", `Failed Case D: 03:00 pm`);
+console.assert(formatAs12HourClock("13:00") === "01:00 pm", `Failed Case E: 01:00 pm`);
+console.assert(formatAs12HourClock("15:45") === "03:45 pm", `Failed Case D: 03:45 pm`);
+console.assert(formatAs12HourClock("13:45") === "01:45 pm", `Failed Case E: 01:45 pm`);
+console.assert(formatAs12HourClock("08:45") === "08:45 am", `Failed Case F: 08:45 am`);
+
+console.log("All current assertions completed!");