Barcelona | oct2025-1 | Xinxi Chen | Sprint2

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

@@ -1,5 +1,7 @@
 // Predict and explain first...
 //  =============> write your prediction here
+There is a syntax error. Str is a parameter, then it has declared again as let str =.
+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
@@ -10,4 +12,9 @@ function capitalise(str) {
 }
 
 // =============> write your explanation here
+//
 // =============> write your new code here
+function capitalise(str) {
+  str = `${str[0].toUpperCase()}${str.slice(1)}`;
+  return str;
+}

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

@@ -2,6 +2,7 @@
 
 // Why will an error occur when this program runs?
 // =============> write your prediction here
+//syntax error, decimalNumber has been declared as the parameter, then it to be declared again as const decimalNumber.
 
 // Try playing computer with the example to work out what is going on
 
@@ -11,10 +12,21 @@ function convertToPercentage(decimalNumber) {
 
   return percentage;
 }
-
 console.log(decimalNumber);
 
+
+
 // =============> write your explanation here
+//Since the decimalNumber is a parameter, it's not neccesary to declare it again as const and assign it a value.
+//Only need to assign the specific decimalNumber in console.log with the function name and delete the redeclaration of const decimalNumber = 0.5.
 
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+
+function convertToPercentage(decimalNumber) {
+  const percentage = `${decimalNumber * 100}%`;
+
+  return percentage;
+}
+
+console.log(convertToPercentage(1));

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

@@ -4,17 +4,22 @@
 // this function should square any number but instead we're going to get an error
 
 // =============> write your prediction of the error here
+The parameter 3 is an error.
+
 
 function square(3) {
     return num * num;
 }
 
 // =============> write the error message here
-
+function square(3)
 // =============> explain this error message here
-
+The parameter should 2 is a problem. It should be num, otherwise there is no declaration of num.
 // 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 +1,20 @@
 // Predict and explain first...
 
 // =============> write your prediction here
-
+//Probably the function is not defined.
 function multiply(a, b) {
   console.log(a * b);
 }
 
-console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
+//console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
 
 // =============> write your explanation here
-
+//Because the function doesn't return to any result. It's only to print the multiply of the parameters.
 // 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

@@ -1,6 +1,6 @@
 // Predict and explain first...
 //  =============> write your prediction here
-
+//It's undefined.
 function sum(a, b) {
   return;
   a + b;
@@ -9,5 +9,11 @@ function sum(a, b) {
 console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
 
 // =============> write your explanation here
+//It returns nothing, and the expression a + b is incomplete.
 // 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 +2,7 @@
 
 // Predict the output of the following code:
 // =============> Write your prediction here
-
+The results are all 3.
 const num = 103;
 
 function getLastDigit() {
@@ -15,10 +15,24 @@ 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
+Because num has been declared as a globle const variable which is 103, then the num value can't be changed. There is no parameter as well.
 // =============> write your explanation here
+Since it's a const globle variable, the num's value is alway 103, that's why no matter what's the value type in console.log the result is always the same.
 // Finally, correct the code to fix the problem
 // =============> write your new code here
 
+
+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

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
-}
+    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 +14,7 @@
 // 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.replace(/([a-z])([A-Z])/g,'$1_$2').toUpperCase();
+}
+console.log(toUpperSnakeCase("Lord Of The Rings"));

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

@@ -4,3 +4,16 @@
 // 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);
+    console.log(`£${pounds}.${pence}`);
+}
+toPounds("399p");
+toPounds("99p");
+toPounds("3p");
+toPounds("1399p");

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

@@ -10,6 +10,7 @@ function formatTimeDisplay(seconds) {
 
   return `${pad(totalHours)}:${pad(remainingMinutes)}:${pad(remainingSeconds)}`;
 }
+console.log(formatTimeDisplay(61));
 
 // You will need to play computer with this example - use the Python Visualiser https://pythontutor.com/visualize.html#mode=edit
 // to help you answer these questions
@@ -18,6 +19,7 @@ function formatTimeDisplay(seconds) {
 
 // a) When formatTimeDisplay is called how many times will pad be called?
 // =============> write your answer here
+// 3 times. First, pad(totalHours); Second, pad(remainingMinutes); Third, pad(remainingSeconds).
 
 // Call formatTimeDisplay with an input of 61, now answer the following:
 
@@ -26,9 +28,10 @@ function formatTimeDisplay(seconds) {
 
 // c) What is the return value of pad is called for the first time?
 // =============> write your answer here
-
+  0
 // 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
-
+  00, because after the function formatTimeDisplay(61) execute its argorithm, the hour value is 0, then function pad(num) converts all the num to 2 digit format. 
 // 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
+  01, because after the function formatTimeDisplay(61) execute its argorithm, the hour value is 1, then function pad(num) converts all the num to 2 digit format, thus why it's 01.

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

@@ -3,22 +3,32 @@
 // Your task is to write tests for as many different groups of input data or edge cases as you can, and fix any bugs you find.
 
 function formatAs12HourClock(time) {
-  const hours = Number(time.slice(0, 2));
-  if (hours > 12) {
-    return `${hours - 12}:00 pm`;
+  let hours = Number(time.slice(0, 2));
+  const minutes = time.slice(3, 5);
+  let ampm = "am";
+
+  if (hours === 0) {
+    hours = 12;
+    ampm = "am";
+  }
+  else if (hours >= 12) {
+    ampm = "pm";
+    if (hours > 12) {
+      hours -= 12;
+    }
   }
-  return `${time} am`;
+  return `${hours}:${minutes} ${ampm}`;
 }
 
-const currentOutput = formatAs12HourClock("08:00");
-const targetOutput = "08:00 am";
+const currentOutput = formatAs12HourClock("00:00");
+const targetOutput = "12:00 am";
 console.assert(
   currentOutput === targetOutput,
   `current output: ${currentOutput}, target output: ${targetOutput}`
 );
 
-const currentOutput2 = formatAs12HourClock("23:00");
-const targetOutput2 = "11:00 pm";
+const currentOutput2 = formatAs12HourClock("24:00");
+const targetOutput2 = "12:00 pm";
 console.assert(
   currentOutput2 === targetOutput2,
   `current output: ${currentOutput2}, target output: ${targetOutput2}`