London | 26-ITP-January | Karla Grajales | Sprint 2 | Coursework/sprint 2

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

@@ -4,10 +4,25 @@
 // 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;
-}
+// function capitalise(str) {
+//   const capiLetter = `${str[0].toUpperCase()}${str.slice(1)}`;
+//   return capiLetter;
+// }
 
 // =============> write your explanation here
+
+  // The original code failed for two reasons: first the function was never invoke,
+  // there was a variable naming conflict with the function scope.
+  // Since str was already defined as a parameter, can not be used to re-declare 
+  // a variable inside the function. To fix this, I moved the processed directly and
+  // returned the result directly
+
 // =============> write your new code here
+
+
+function capitalise(str) {
+
+  return `${str[0].toUpperCase()}${str.slice(1)}`;
+}
+
+console.log(capitalise("hello")); 

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

@@ -5,16 +5,36 @@
 
 // Try playing computer with the example to work out what is going on
 
-function convertToPercentage(decimalNumber) {
-  const decimalNumber = 0.5;
-  const percentage = `${decimalNumber * 100}%`;
+// function convertToPercentage(decimalNumber) {
+//   const decimalNumber = 0.5;
+//   const percentage = `${decimalNumber * 100}%`;
 
-  return percentage;
-}
+//   return percentage;
+// }
 
-console.log(decimalNumber);
+// console.log(decimalNumber);
 
 // =============> write your explanation here
 
+// This function will throw a SyntaxError because decimalNumber 
+// is being redeclared inside the same scope as the parameter. 
+// Additionally, the function ignores the input parameter 
+// because the value is hardcoded inside the body. 
+// Finally, the console.log will throw a ReferenceError 
+// because it tries to access a local variable from the global scope. 
+// To fix this, we must remove the internal declaration to use the 
+// parameter dynamically and invoke the function correctly.
+
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+
+
+
+// function convertToPercentage(num) {
+//   return  `${num * 100}%`;;
+// }
+
+
+const convertToPercentage = (num) => `${num * 100}%`;
+
+console.log(convertToPercentage(0.80));

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

@@ -5,16 +5,30 @@
 
 // =============> write your prediction of the error here
 
-function square(3) {
-    return num * num;
-}
+// function square(3) {
+//     return num * num;
+// }
+
 
 // =============> write the error message here
 
+    // It will throw a syntaxError because a literal Number(3) cannot be used
+    // as a function parameter. furthermore, the return statement will 
+    // cause an referenceError because it attempts to use a var num that 
+    // has no been defined. To fix this, we must replace the number in 
+    // the function with the identifier num.
+
 // =============> explain this error message here
 
 // Finally, correct the code to fix the problem
 
 // =============> write your new code here
 
 
+
+function square(num) {
+    return num * num;
+}
+
+
+console.log(square(9));  

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

@@ -2,13 +2,22 @@
 
 // =============> write your prediction here
 
-function multiply(a, b) {
-  console.log(a * b);
-}
+// 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
 
+//will display the first console.log and make the operation 10 * 32
+// but the second console.log will throw undefined because
+// the function does not have a return statement.
+
 // 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

@@ -1,13 +1,24 @@
 // Predict and explain first...
 //  =============> write your prediction here
 
-function sum(a, b) {
-  return;
-  a + b;
-}
+// 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)}`);
 
 // =============> write your explanation here
+
+  // This function will return undefined because the return statement executes first.
+  // since the operation a + b is after the return statement, it will never be executed.
+
+
 // 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 + 32 is ${sum(10, 32)}`);

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

@@ -3,22 +3,49 @@
 // Predict the output of the following code:
 // =============> Write your prediction here
 
-const num = 103;
+  // The output will always be 3 for all cases. Even though 
+  // arguments are passed to the function, it lacks parameter 
+  // to receive them. Therefore, the function defaults to using
+  // the global scope constant num = 103 every time it runs.
 
-function getLastDigit() {
-  return num.toString().slice(-1);
-}
+// const num = 103;
 
-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)}`);
+// 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)}`);
 
 // 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 function getLastDigit is not working properly because 
+  // it is hardcoded to use the global constant num. Since 
+  // the function definition does not include any parameters, 
+  // it ignores the arguments (42, 105, 806) passed during the 
+  // call. As a result, it always calculates the last digit of 103, which is 3
+
 // Finally, correct the code to fix the problem
 // =============> write your new code here
 
+const num = 103; //this now is a ghost variable and is not used in the function
+
+function getLastDigit(value) {
+  return value.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
+// Explain why getLastDigit is not working properly - correct the problem

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

@@ -15,5 +15,18 @@
 // 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 the BMI of someone based off their weight and height
+  const squareHeight = height * height;
+  const operation = weight / squareHeight;
+  const bmi = Math.round(operation * 10) / 10; 
+
+  return bmi;
+}
+
+
+console.log(calculateBMI(70, 1.73)); 
+
+
+// to get 23.4 we use the Math.round(operation * 10) / 10; to move the decimal 
+// one place to the right, round it to the nearest whole number, then move it 
+// back by dividing by 10.

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

@@ -12,5 +12,14 @@
 // 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
+// Use the MDN string documentation to help you find a solutio
 // This might help https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/toUpperCase
+
+
+function toUpperSnakeCase(str) {
+
+    return str.toUpperCase().replaceAll(" ", "_");
+}
+
+// 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

@@ -4,3 +4,78 @@
 // 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
+
+
+// =============================== Original Code ========================
+// const penceString = "399p";
+
+// 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");
+
+// console.log(`£${pounds}.${pence}`);
+
+
+
+// =============================== Refactoring ========================
+
+// to make robust function we can use some maths methods to reduce the looping and 
+// return only the numbers, like this: /[^\d]/g, with that we can remove all 
+// characters that are no number, then we can convert the number into decimals by 
+// dividing by 100.
+
+//padStart method can be used to ensure that strings have a minimum length, no used in numbers
+//The toFixed() method formats a number using fixed-point notation.
+
+// In programming, we call this a Regular Expression (Regex). Think of it as a custom filter for text.
+
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Regular_expressions
+
+// REGEX BREAKDOWN
+
+// Delimiters (/ /): The "brackets" that mark the start and end of the Regex.
+// Non-digit (\D): Matches any character that is NOT a number (0-9).
+// Negated Set ([^\d]): The long version of \D (Anything that is NOT a digit).
+// Global Flag (g): Tells the code to clean the entire string, not just the first letter.
+// Empty String (''): Replaces the "bad" characters with nothing (deleting them).
+// Example: "£1.50p" -> "150"
+// const onlyNumbers = str.replace(/\D/g, '');
+
+// =============================== Reusable Code ========================
+
+
+function toPounds(str){
+
+    const onlyNumbers = str.replace(/[^\d]/g, '');
+    const decimals = (onlyNumbers/100).toFixed(2);
+
+    return `£${decimals}`;
+};
+
+
+
+// =============================== 1st way to test ========================
+
+const examples = ["79p", "hfhbgjk1p", "150p", "£2.50", "11000"];
+for (const example of examples) {
+    console.log(toPounds(example));
+}
+
+
+// =============================== 2nd way to test ========================
+
+// const examples2 = ["79p", "hfhbgjk1p", "150p", "£2.50", "12000"];
+// for (const example of examples2) {
+//   console.log(`Original: ${example} -> Formatted: ${toPounds(example)}`);
+// };

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

@@ -3,32 +3,46 @@ function pad(num) {
 }
 
 function formatTimeDisplay(seconds) {
-  const remainingSeconds = seconds % 60;
+  const remainingSeconds = seconds % 60; 
+  //get the remaining seconds after dividing by 61/60 = 1 remainder 1
   const totalMinutes = (seconds - remainingSeconds) / 60;
+  //get seconds = 1 - 60; result is 60/60 =  total minutes 1
   const remainingMinutes = totalMinutes % 60;
+  //the remainingMinutes  = 1 & 60 = 1; because the totalMinutes is less than 
+  // 60 the number will always the number from left side of the modulus operator
   const totalHours = (totalMinutes - remainingMinutes) / 60;
 
   return `${pad(totalHours)}:${pad(remainingMinutes)}:${pad(remainingSeconds)}`;
 }
 
+
+console.log(formatTimeDisplay(61)); // Should print "00:01:01"    
+
 // 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
+// pad function will be called 3 times when formatTimeDisplay is called.
 
-// Call formatTimeDisplay with an input of 61, now answer the following:
+//==== 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
+// =============> write your answer here 
+// The value assigned to num when pad is called for the first time is 0.
 
 // c) What is the return value of pad is called for the first time?
 // =============> write your answer here
+// The return value of pad when it is called for the first time is "00".
+// because num is 0, and when we convert it to a string and pad it to 2 
+// characters with leading zeros, it becomes "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
+// The value assigned to num when pad is called for the last time in this program is 1
 
 // 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
+// The return value assigned to num when pad is called for the last time in this program is "01".