Glasgow | 26-ITP-May | Sandani Kannangara | Sprint 2 |Coursework

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

@@ -1,13 +1,30 @@
-// Predict and explain first...
-//  =============> write your prediction here
+// Predict and explain :
+//The code will throw a SyntaxError : 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) {
+// Original code :
+/*function capitalise(str) {
   let str = `${str[0].toUpperCase()}${str.slice(1)}`;
   return str;
+}*/
+
+//----------------------------------------------------------------------------------------------------------
+
+// Corrected code :
+function capitalise(str) {
+  let capitaliseStr = `${str[0].toUpperCase()}${str.slice(1)}`;
+  return capitaliseStr;
 }
 
-// =============> write your explanation here
-// =============> write your new code here
+// call the function capitalise with a string input :
+capitalise("javascript");
+
+//----------------------------------------------------------------------------------------------------------
+
+// interpretation of the error message / Why an error is occurring :
+//SyntaxError: Identifier 'str' has already been declared.
+//str is already declared as a function parameter.
+//Parameter is already a variable inside the function.
+//Then, try to declare it again using let str as a local parameter.
+//JavaScript does NOT allow two variables with the same name in the same function scope.

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

@@ -1,20 +1,28 @@
-// Predict and explain first...
+// Predict and explain:
+// Error occurs because decimalNumber is declared twice inside the function, and it is also a local variable not accessible outside the function.
 
-// Why will an error occur when this program runs?
-// =============> write your prediction here
+//----------------------------------------------------------------------------------------------------------
 
-// Try playing computer with the example to work out what is going on
-
-function convertToPercentage(decimalNumber) {
+// Original code
+/*function convertToPercentage(decimalNumber) {
   const decimalNumber = 0.5;
   const percentage = `${decimalNumber * 100}%`;
-
   return percentage;
 }
+console.log(decimalNumber);*/
+
+//----------------------------------------------------------------------------------------------------------
+
+// My explanation :
+// decimalNumber is already declared as a function parameter, so it cannot be declared again with const inside the function.
+// Also, decimalNumber only exists inside the function, so it cannot be used in console.log outside the function.
 
-console.log(decimalNumber);
+//----------------------------------------------------------------------------------------------------------
 
-// =============> write your explanation here
+// Corrected code :
+function convertToPercentage(decimalNumber) {
+  const percentage = `${decimalNumber * 100}%`;
+  return percentage;
+}
 
-// 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 +1,33 @@
+// Predict and explain :
+// The code will throw a SyntaxError because a number is used as a parameter name.
 
-// Predict and explain first BEFORE you run any code...
+//----------------------------------------------------------------------------------------------------------
 
-// this function should square any number but instead we're going to get an error
+// My prediction of the error :
+//SyntaxError: Unexpected identifier
 
-// =============> write your prediction of the error here
+//----------------------------------------------------------------------------------------------------------
 
-function square(3) {
-    return num * num;
-}
+// Original code :
+/*function square(3) {
+  return num * num;
+}*/
 
-// =============> write the error message here
+//----------------------------------------------------------------------------------------------------------
 
-// =============> explain this error message here
+// The error message :
+//SyntaxError: Unexpected number
 
-// Finally, correct the code to fix the problem
+//----------------------------------------------------------------------------------------------------------
 
-// =============> write your new code here
+// Explaination of the error message :
+// Function parameters must be valid variable names (identifiers).
+// The code uses the number 3 as a parameter, but numbers cannot be used as parameter names.
 
+//----------------------------------------------------------------------------------------------------------
 
+// Corrected code :
+function square(num) {
+  return num * num;
+}
+console.log(square(5));

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

@@ -1,14 +1,29 @@
-// Predict and explain first...
+// My prediction :
+// The function will print 320.
+// Then the second console.log will print:
+// "The result of multiplying 10 and 32 is undefined"
+// because multiply() does not return a value.
 
-// =============> write your prediction here
+//----------------------------------------------------------------------------------------------------------
 
-function multiply(a, b) {
+// Original code :
+/*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
+// my explanation :
+// multiply() uses console.log() to display the result, but it does not return it.
+// Functions that do not return a value return undefined by default.
+// Therefore, multiply(10, 32) evaluates to undefined in the template string.
 
-// Finally, correct the code to fix the problem
-//  =============> write your new code here
+//----------------------------------------------------------------------------------------------------------
+
+//new code :
+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 +1,28 @@
-// Predict and explain first...
-//  =============> write your prediction here
+// Predict and explain :
+// The function will return undefined.
+// Therefore, the output will be:
+// "The sum of 10 and 32 is undefined"
 
-function sum(a, b) {
+//----------------------------------------------------------------------------------------------------------
+
+// Original code :
+/*function sum(a, b) {
   return;
   a + b;
 }
+console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);*/
 
-console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
+//----------------------------------------------------------------------------------------------------------
+
+// My explanation :
+// The return statement ends the function immediately.
+// Because return is on its own line, the expression a + b is never executed.
+// As a result, the function returns undefined.
 
-// =============> write your explanation here
-// Finally, correct the code to fix the problem
-//  =============> write your new code here
+//----------------------------------------------------------------------------------------------------------
+
+//new code :
+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

@@ -1,24 +1,51 @@
-// Predict and explain first...
+// Predict and explain :
+//The getLastDigit function always returns the last digit of 103, because it does not use the input value passed to it. Instead, it uses the global variable num.
+//So every call returns 3.
 
-// Predict the output of the following code:
-// =============> Write your prediction here
+//----------------------------------------------------------------------------------------------------------
 
-const num = 103;
+// My Prediction of the output of the Original code :
+//The last digit of 42 is 3
+//The last digit of 105 is 3
+//The last digit of 806 is 3
+
+//----------------------------------------------------------------------------------------------------------
+
+//Original code :
+/*const num = 103;
 
 function getLastDigit() {
   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)}`);*/
+
+//----------------------------------------------------------------------------------------------------------
+
+// output of the Original code :
+//Answer :
+//The last digit of 42 is 3
+//The last digit of 105 is 3
+//The last digit of 806 is 3
+
+//----------------------------------------------------------------------------------------------------------
+
+// Explaination of why the output the way it is :
+// The function does not use its parameter correctly.
+// It ignores the value passed into it and instead uses the global variable num.
+// That is why all outputs are the same.
+
+//----------------------------------------------------------------------------------------------------------
+
+//new code :
+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)}`);
 
-// 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

@@ -14,6 +14,9 @@
 // Then when we call this function with the weight and height
 // 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 ** 2).toFixed(1));
+}
+console.log(calculateBMI(70, 1.73));

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

@@ -14,3 +14,11 @@
 // 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 convertToUpperSnakeCase(str) {
+  return str.trim().toUpperCase().split(" ").join("_");
+}
+
+console.log(convertToUpperSnakeCase(" 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(pence) {
+  const penceValue = pence.slice(0, -1).padStart(3, "0");
+  return `£${penceValue.slice(0, -2)}.${penceValue.slice(-2)}`;
+}
+
+console.log(toPounds("90p"));
+
+let penceArray = [
+  ["399p", "£3.99"],
+  ["9p", "£0.09"],
+  ["50p", "£0.50"],
+  ["1002p", "£10.02"],
+  ["1900p", "£19.00"],
+];
+for (const [input, expectedOutput] of penceArray) {
+  const currentOutput = toPounds(input);
+  console.assert(
+    currentOutput === expectedOutput,
+    `Current output is ${currentOutput}. Expected outout is ${expectedOutput}`
+  );
+}

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

@@ -15,24 +15,62 @@ 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
 
+//---------------------------------------------------------------------------------------------
+
 // Questions
 
+//---------------------------------------------------------------------------------------------
+
 // a) When formatTimeDisplay is called how many times will pad be called?
-// =============> write your answer here
+// 3 times.
+// pad(totalHours)
+// pad(remainingMinutes)
+// pad(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
+// 0
+// remainingSeconds = 61 % 60 = 1
+// totalMinutes = (61 - 1) / 60 = 1
+// remainingMinutes = 1 % 60 = 1
+// totalHours = (1 - 1) / 60 = 0
+// First call: pad(totalHours)
+// So, num = 0.
+
+//---------------------------------------------------------------------------------------------
 
 // c) What is the return value of pad is called for the first time?
-// =============> write your answer here
+// "00"
+// num = 0
+// numString = "0"
+// Since numString.length is 1, the while loop runs once.
+// "0" + "0" = "00"
+// The function 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
+// 1
+// The last call to pad is pad(remainingSeconds).
+// When seconds is 61, remainingSeconds is 61 % 60, which equals 1.
+// Therefore, num is assigned the value 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
+// "01"
+// The last call is pad(1).
+// Inside the function, 1 is converted to the string "1".
+// Since its length is less than 2, a leading zero is added,
+// making it "01".
+// The function then returns "01".