Birmingham | 26-ITP-May | Gabriel Pawuoi| Sprint 2 | Coursework

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

@@ -1,13 +1,23 @@
 // Predict and explain first...
-//  =============> write your prediction here
+// Prediction: SyntaxError because `str` is re-declared with `let` inside the function
+// where it already exists as a parameter. You cannot use `let` to re-declare a variable
+// that already exists in the same scope.
 
 // call the function capitalise with a string input
 // interpret the error message and figure out why an error is occurring
 
+// Original broken code:
+// function capitalise(str) {
+//   let str = `${str[0].toUpperCase()}${str.slice(1)}`;
+//   return str;
+// }
+
+// Explanation: The parameter `str` already exists in the function scope.
+// Using `let str` tries to re-declare it, which is a SyntaxError.
+// Instead of reassigning `str` (which represents the original input),
+// we use a new const `capitalisedStr` to make it clear this is a different value.
+
 function capitalise(str) {
-  let str = `${str[0].toUpperCase()}${str.slice(1)}`;
-  return str;
+  const capitalisedStr = `${str[0].toUpperCase()}${str.slice(1)}`;
+  return capitalisedStr;
 }
-
-// =============> write your explanation here
-// =============> write your new code here

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

@@ -1,20 +1,28 @@
 // Predict and explain first...
 
 // Why will an error occur when this program runs?
-// =============> write your prediction here
+// Prediction: Two errors — (1) re-declaring decimalNumber with const inside the function
+// when it is already a parameter causes a SyntaxError.
+// (2) console.log(decimalNumber) outside the function will throw ReferenceError because
+// decimalNumber is not defined in the outer scope.
 
 // Try playing computer with the example to work out what is going on
 
+// Original broken code:
+// function convertToPercentage(decimalNumber) {
+//   const decimalNumber = 0.5;
+//   const percentage = `${decimalNumber * 100}%`;
+//   return percentage;
+// }
+// console.log(decimalNumber);
+
+// Explanation: The parameter decimalNumber already exists in the function scope;
+// const re-declaration is illegal. Also, decimalNumber is not accessible outside the function.
+// Fix: remove the const re-declaration inside the function, and pass a value when calling it.
+
 function convertToPercentage(decimalNumber) {
-  const decimalNumber = 0.5;
   const percentage = `${decimalNumber * 100}%`;
-
   return percentage;
 }
 
-console.log(decimalNumber);
-
-// =============> write your explanation here
-
-// Finally, correct the code to fix the problem
-// =============> write your new code here
+console.log(convertToPercentage(0.5));

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

@@ -1,20 +1,19 @@
-
 // Predict and explain first BEFORE you run any code...
 
 // this function should square any number but instead we're going to get an error
 
-// =============> write your prediction of the error here
-
-function square(3) {
-    return num * num;
-}
-
-// =============> write the error message here
+// Prediction: SyntaxError — a function parameter must be a valid identifier, not a number literal.
 
-// =============> explain this error message here
-
-// Finally, correct the code to fix the problem
-
-// =============> write your new code here
+// Original broken code:
+// function square(3) {
+//     return num * num;
+// }
 
+// Error message: SyntaxError: Unexpected number
+// Explanation: `3` is a number literal and cannot be used as a parameter name.
+// Parameters must be valid identifiers (variable names).
+// Fix: use a named parameter like `num`.
 
+function square(num) {
+  return num * num;
+}

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

@@ -1,14 +1,19 @@
 // Predict and explain first...
+// Prediction: The template literal will print "undefined" for the function result because
+// multiply uses console.log internally but does not return a value (returns undefined).
 
-// =============> write your prediction here
+// Original broken code:
+// function multiply(a, b) {
+//   console.log(a * b);
+// }
+// console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
+
+// Explanation: Functions without a return statement return undefined.
+// The outer console.log then interpolates undefined into the string.
+// Fix: replace console.log inside multiply with a return statement.
 
 function multiply(a, b) {
-  console.log(a * b);
+  return a * b;
 }
 
 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
-//  =============> write your new code here

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

@@ -1,13 +1,20 @@
 // Predict and explain first...
-//  =============> write your prediction here
+// Prediction: The sum will print "undefined" because return; exits the function
+// immediately without a value, so a + b is never evaluated.
+
+// Original broken code:
+// function sum(a, b) {
+//   return;
+//   a + b;
+// }
+// console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
+
+// Explanation: return; with no expression returns undefined.
+// The a + b on the next line is unreachable dead code and is never executed.
+// Fix: put a + b on the same line as return.
 
 function sum(a, b) {
-  return;
-  a + b;
+  return a + b;
 }
 
 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

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

@@ -1,24 +1,29 @@
 // Predict and explain first...
 
 // Predict the output of the following code:
-// =============> Write your prediction here
+// Prediction: All three logs will print "3" (the last digit of the module-level const num = 103)
+// because getLastDigit ignores its parameter and always uses the outer num.
+// Expected output:
+//   The last digit of 42 is 3
+//   The last digit of 105 is 3
+//   The last digit of 806 is 3
 
-const num = 103;
+// Original broken code:
+// const num = 103;
+// function getLastDigit() {
+//   return num.toString().slice(-1);
+// }
 
-function getLastDigit() {
+// Actual output matched prediction — all printed "3".
+
+// Explanation: The function has no parameter, so any argument passed in is discarded.
+// It always reads the outer `num` variable which is 103.
+// Fix: add a parameter to getLastDigit and use it instead of the outer variable.
+
+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)}`);
-
-// Now run the code and compare the output to your prediction
-// =============> write the output here
-// 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
-
-// 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

@@ -15,5 +15,5 @@
 // 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
+  return Number((weight / (height * height)).toFixed(1));
 }

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

@@ -1,16 +1,6 @@
-// A set of words can be grouped together in different cases.
+function toUpperSnakeCase(str) {
+  return str.replaceAll(" ", "_").toUpperCase();
+}
 
-// For example, "hello there" in snake case would be written "hello_there"
-// UPPER_SNAKE_CASE means taking a string and writing it in all caps with underscores instead of spaces.
-
-// Implement a function that:
-
-// Given a string input like "hello there"
-// When we call this function with the input string
-// it returns the string in UPPER_SNAKE_CASE, so "HELLO_THERE"
-
-// Another example: "lord of the rings" should be "LORD_OF_THE_RINGS"
-
-// 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
+console.log(toUpperSnakeCase("hello there"));       // "HELLO_THERE"
+console.log(toUpperSnakeCase("lord of the rings")); // "LORD_OF_THE_RINGS"

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

@@ -1,6 +1,12 @@
-// In Sprint-1, there is a program written in interpret/to-pounds.js
+function toPounds(penceString) {
+  const withoutP = penceString.substring(0, penceString.length - 1);
+  const padded = withoutP.padStart(3, "0");
+  const pounds = padded.substring(0, padded.length - 2);
+  const pence = padded.substring(padded.length - 2).padEnd(2, "0");
+  return `£${pounds}.${pence}`;
+}
 
-// You will need to take this code and turn it into a reusable block of code.
-// 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
+console.log(toPounds("399p"));  // £3.99
+console.log(toPounds("9p"));    // £0.09
+console.log(toPounds("50p"));   // £0.50
+console.log(toPounds("1000p")); // £10.00

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

@@ -21,18 +21,19 @@ function formatTimeDisplay(seconds) {
 // Questions
 
 // a) When formatTimeDisplay is called how many times will pad be called?
-// =============> write your answer here
+// =============> pad is called 3 times per call to formatTimeDisplay (once for totalHours, once for remainingMinutes, once for remainingSeconds).
 
 // Call formatTimeDisplay with an input of 61, now answer the following:
+// (remainingSeconds = 1, totalMinutes = 1, remainingMinutes = 1, totalHours = 0)
 
 // b) What is the value assigned to num when pad is called for the first time?
-// =============> write your answer here
+// =============> num = 0 (totalHours), because totalHours is the first argument in the template literal.
 
-// c) What is the return value of pad is called for the first time?
-// =============> write your answer here
+// c) What is the return value of pad when it is called for the first time?
+// =============> "00" — "0".length < 2, so "0" is prepended, giving "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
+// =============> num = 1 (remainingSeconds). It is the last argument passed in the template literal, so pad is called with it last.
 
 // 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
+// =============> "01" — "1".length < 2, so "0" is prepended, giving "01".