Complete Sprint 3 Modules

Author: Thabimalindi

Sprint-3/1-key-errors/0.js

@@ -1,13 +1,23 @@
 // Predict and explain first...
-//  =============> write your prediction here
+// I predict an error will occur because str is already the name of the function parameter.
 
 // call the function capitalise with a string input
+capitalise("hello");
+
 // 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
+// The error occurs because str is declared twice in the same scope.
+// str is already a parameter of the capitalise function, so we cannot declare it again using let.
+
+// New code:
+function capitalise(str) {
+  str = `${str[0].toUpperCase()}${str.slice(1)}`;
+  return str;
+}
+
+console.log(capitalise("hello"));

Sprint-3/1-key-errors/1.js

@@ -1,7 +1,8 @@
 // Predict and explain first...
 
 // Why will an error occur when this program runs?
-// =============> write your prediction here
+// I predict an error will occur because decimalNumber is already the name
+// of the function parameter and it is declared again using const.
 
 // Try playing computer with the example to work out what is going on
 
@@ -14,7 +15,15 @@ function convertToPercentage(decimalNumber) {
 
 console.log(decimalNumber);
 
-// =============> write your explanation here
+// The error occurs because decimalNumber is declared twice in the same scope.
+// It is already a parameter of the function, so it cannot be declared again using const.
 
 // 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(0.5));

Sprint-3/1-key-errors/2.js

@@ -1,20 +1,25 @@
-
 // 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
+// I predict there will be a syntax error because 3 is a number
+// and a function parameter must be a valid variable name.
 
-function square(3) {
-    return num * num;
-}
+// function square(3) {
+//     return num * num;
+// }
 
-// =============> write the error message here
+// Error message:
+// Identifier expected.
 
-// =============> explain this error message here
+// The error occurs because 3 is being used as the function parameter.
+// A function parameter must be a valid variable name, such as num.
+// The number 3 should be passed into the function as an argument instead.
 
 // Finally, correct the code to fix the problem
 
-// =============> write your new code here
-
+function square(num) {
+    return num * num;
+}
 
+console.log(square(3));

Sprint-3/2-mandatory-debug/0.js

@@ -1,14 +1,24 @@
 // Predict and explain first...
 
-// =============> write your prediction here
+// I predict the multiplication will calculate 320,
+// but the final message will show undefined because the function
+// logs the result instead of returning it.
 
 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 multiply function uses console.log() to display the result,
+// but it does not return a value.
+// A function without a return statement returns undefined.
+// This is why the final message contains undefined.
 
 // 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-3/2-mandatory-debug/1.js

@@ -1,5 +1,7 @@
 // Predict and explain first...
-//  =============> write your prediction here
+
+// I predict the result will be undefined because the return statement
+// does not return the result of a + b.
 
 function sum(a, b) {
   return;
@@ -8,6 +10,14 @@ function sum(a, b) {
 
 console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
 
-// =============> write your explanation here
+// The function returns immediately when it reaches the return statement.
+// Because there is no value after return, the function returns undefined.
+// The line a + b is never reached.
+
 // 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-3/2-mandatory-debug/2.js

@@ -1,7 +1,8 @@
 // Predict and explain first...
 
 // Predict the output of the following code:
-// =============> Write your prediction here
+// I predict that all three console.log statements will show 3
+// because the function uses the global variable num, which is 103.
 
 const num = 103;
 
@@ -14,11 +15,24 @@ 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 output is:
+// 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 getLastDigit function does not have a parameter.
+// It always uses the global variable num, which has the value 103.
+// Therefore, the arguments 42, 105 and 806 are ignored.
+// The last digit of 103 is 3, so the function returns 3 every time.
+
 // 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
+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-3/3-mandatory-implement/1-bmi.js

@@ -17,3 +17,7 @@
 function calculateBMI(weight, height) {
   // return the BMI of someone based off their weight and height
 }
+function calculateBMI(weight, height) {
+  const bmi = weight / (height * height);
+  return bmi.toFixed(1);
+}

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

@@ -14,3 +14,6 @@
 // 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().replaceAll(" ", "_");
+}

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

@@ -1,6 +1,23 @@
-// In Sprint-1, there is a program written in 3-mandatory-interpret/3-to-pounds.js
+function toPounds(penceString) {
+  const penceStringWithoutTrailingP = penceString.substring(
+    0,
+    penceString.length - 1
+  );
 
-// 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.
+  const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
 
-// You should call this function a number of times to check it works for different inputs
+  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("50p"));
+console.log(toPounds("1250p"));

Sprint-3/4-mandatory-interpret/time-format.js

@@ -15,24 +15,28 @@ function formatTimeDisplay(seconds) {
   return `${pad(totalHours)}:${pad(remainingMinutes)}:${pad(remainingSeconds)}`;
 }
 
-// You will need to play computer with this example - use the Python Visualiser https://pythontutor.com/visualize.html#mode=edit
+// You will need to play computer with this example - use the Python Visualiser
 // to help you answer these questions
 
 // Questions
 
 // a) When formatTimeDisplay is called how many times will pad be called?
-// =============> write your answer here
+// pad will be called 3 times.
 
 // 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
+// The value assigned to num is 0.
 
 // c) What is the return value of pad when it is called for the first time?
-// =============> write your answer here
+// The return value is "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
+// d) What is the value assigned to num when pad is called for the last time in this program? Explain your answer
+// The value assigned to num is 1.
+// The last call is pad(remainingSeconds), and when the input is 61,
+// remainingSeconds is 1.
 
-// 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
+// e) What is the return value of pad when it is called for the last time in this program? Explain your answer
+// The return value is "01".
+// num is converted to the string "1". Because it has fewer than 2 characters,
+// the while loop adds a "0" to the beginning, producing "01".