London | 26-ITP-January | Khaliun Baatarkhuu | Sprint 2 | Coursework.

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

@@ -1,13 +1,22 @@
 // Predict and explain first...
-//  =============> write your prediction here
+//  =============> write your prediction here: We'll get an error message because "str" paramater has been declared already,
+//using it again inside the function will clash due to redaclaration. 
 
 // 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;
+//}
+
+// =============> write your explanation here: Identifier 'str' has already been declared, 
+//redaclaration in the same scope throws up the error message 
+// =============> write your new code here: 
 function capitalise(str) {
-  let str = `${str[0].toUpperCase()}${str.slice(1)}`;
-  return str;
+  let newStr = `${str[0].toUpperCase()}${str.slice(1)}`;
+  return newStr;
 }
 
-// =============> write your explanation here
-// =============> write your new code here
+//Above code works because we have used another variable "newStr", avoiding redeclaration.
+

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

@@ -1,20 +1,47 @@
 // Predict and explain first...
 
 // Why will an error occur when this program runs?
-// =============> write your prediction here
+// =============> write your prediction here: potential error, decimalNumber has already been declared, can't redaclare it again with a new variable in the same scope.
+//another error could be, console.log will try to access a local variable from the global scope. 
 
 // Try playing computer with the example to work out what is going on
 
+// step one: function convertToPercentage(decimalNumber)
+// function created with a parameter named (decimalNumber)
+// step two: const decimalNumber = 0.5;
+// error occurs because decimalNumber has been declared already in the fucntion, cannot declare another one with the same name , in the same scope. 
+// program stops.
+// we have fixed the first error. Code runs again.
+// step three:  const percentage = `${decimalNumber * 100}%`;
+// new variable called percentage created, then the JS code is inserted, where decimalNumber is multiplied by 100.
+// no errors here
+// step four:  return percentage;
+// this line sends the value out of the function then stops the function. No errors so far. 
+// Step five: console.log(decimalNumber);
+// error occurs again, because the value created in step four can't be stored in console.log, due to decimalNumber being a parameter inside the function. Outside the function
+// there is no variable named decimalNumber.
+// we have fixed console.log with (convertToPercentage(0.5), now the result will print properly.
+
+
+
+//function convertToPercentage(decimalNumber) {
+//  const decimalNumber = 0.5;
+//  const percentage = `${decimalNumber * 100}%`;
+
+//  return percentage;
+//}
+
+//console.log(decimalNumber);
+
+// =============> write your explanation here: my error predictions turned out to be true and i have played computer with js code to further illustrate my reasoning. 
+
+// Finally, correct the code to fix the problem
+// =============> write your new code here:
+
 function convertToPercentage(decimalNumber) {
-  const decimalNumber = 0.5;
   const percentage = `${decimalNumber * 100}%`;
-
   return percentage;
 }
 
-console.log(decimalNumber);
-
-// =============> write your explanation here
+console.log(convertToPercentage(0.5));
 
-// Finally, correct the code to fix the problem
-// =============> write your new code here

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

@@ -3,18 +3,30 @@
 
 // this function should square any number but instead we're going to get an error
 
-// =============> write your prediction of the error here
+// =============> write your prediction of the error here: error one, 3 cannot be a parameter name, parameters must be variable names, not values. 
+// Error two, num is not defined. There is no variable named num, it would need to match the name inside the function. 
 
-function square(3) {
-    return num * num;
-}
+//function square(3) {
+//    return num * num;
+//}
+
+// =============> write the error message here:
+
+//Uncaught SyntaxError: Unexpected number
 
-// =============> write the error message here
+//Uncaught SyntaxError: Illegal return statement
 
-// =============> explain this error message here
+// =============> explain this error message here:
+
+// first error message came up because JS found a number instead of a variable for the function.
+// second error message came up because in JS return has to be inside of a function. 
 
 // Finally, correct the code to fix the problem
 
-// =============> write your new code here
+// =============> write your new code here:
+
+function square(num) {
+    return num * num;
+}
 
 

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

@@ -1,14 +1,23 @@
 // Predict and explain first...
 
-// =============> write your prediction here
+// =============> write your prediction here: there will be an error, due to console.log being used incorrectly. Console.log is for displaying but there is no return command to
+//clarify what to send to console.log
+
+//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: I have run the code on node.js and got 'undefined' as an error message. I shall add 'return' instead of the first 'console.log'
+//so that the result can be displayed properly in the second console.log.
+
+// Finally, correct the code to fix the problem
+//  =============> write your new code here:
 
 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 +1,22 @@
 // Predict and explain first...
-//  =============> write your prediction here
+//  =============> write your prediction here: js is a sequential language, as in reads code line by line, so i predict nothing will happen after 'return' is processed and 
+//some sort of an error message will appear. 
+
+//function sum(a, b) {
+// return;
+//  a + b;
+//}
+
+//console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
+
+// =============> write your explanation here: 'undefined' error appeared. Fixed the code by adding the addition on the same line as return.
+
+
+// Finally, correct the code to fix the problem
+//  =============> write your new code here:
 
 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 +1,38 @@
 // Predict and explain first...
 
-// Predict the output of the following code:
-// =============> Write your prediction here
+// Predict the output of the following code
+// =============> Write your prediction here: i think, the console.log will only show '3' because the paramater hasn't been specified in the function. 
 
-const num = 103;
+//const num = 103;
 
-function getLastDigit() {
+//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: I've run the code and got '3' in each console.log line. 
+
+// Explain why the output is the way it is
+// =============> write your explanation here: It's because there is no parameter in the function to differentiate viarable 103 from 42, 105, 806.
+
+
+// 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)}`);
 
-// 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
+
+// it works now, but since cosnt num = 103 is unused, i have removed it. 
 
 // 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 +14,12 @@
 // 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) {
+ function calculateBMI(weight, height) {
+    const bmi = weight / (height * height);
+    return Number(bmi.toFixed(1));
+}
+
+console.log(calculateBMI(88, 1.76));
+
     // return the BMI of someone based off their weight and height
-}
+}

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

@@ -14,3 +14,10 @@
 // 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(" ", "_");
+}
+console.log(toUpperSnakeCase("hello there"));

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

@@ -4,3 +4,20 @@
 // 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)
+    .padEnd(2, "0");
+  return `£${pounds}.${pence}`;
+}

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

@@ -1,34 +1,29 @@
-function pad(num) {
-  return num.toString().padStart(2, "0");
+   return `${pad(totalHours)}:${pad(remainingMinutes)}:${pad(remainingSeconds)}`;
 }
 
-function formatTimeDisplay(seconds) {
-  const remainingSeconds = seconds % 60;
-  const totalMinutes = (seconds - remainingSeconds) / 60;
-  const remainingMinutes = totalMinutes % 60;
-  const totalHours = (totalMinutes - remainingMinutes) / 60;
+console.log(formatTimeDisplay(61));
+console.log(formatTimeDisplay(6671));
+console.log(formatTimeDisplay(832));
 
-  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
 // to help you answer these questions
 
 // Questions
 
 // a) When formatTimeDisplay is called how many times will pad be called?
-// =============> write your answer here
+// =============> 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
+// =============> write your answer here: The value is 0.
 
 // c) What is the return value of pad is called for the first time?
-// =============> write your answer here
+// =============> 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
+// =============> write your answer here: The value is 1 because 61 % 60 leaves 1 second remaining. 
 
 // 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
+// =============> write your answer here: The return value is '01' because return num.toString().padstart(2, '0') formats 1 into '01'.