Birmingham | ITP-Jan | Roman Sanaye | Sprint 2 | Module-Structuring-and-Testing-Data coursework

Sprint-1/1-key-exercises/1-count.js

@@ -4,3 +4,6 @@ count = count + 1;
 
 // Line 1 is a variable declaration, creating the count variable with an initial value of 0
 // Describe what line 3 is doing, in particular focus on what = is doing
+
+// Line 3 is assigning (count + 1) to the variable count. 
+// In other word adding 1 to the variable count.

Sprint-1/1-key-exercises/2-initials.js

@@ -5,7 +5,11 @@ let lastName = "Johnson";
 // Declare a variable called initials that stores the first character of each string.
 // This should produce the string "CKJ", but you must not write the characters C, K, or J in the code of your solution.
 
-let initials = ``;
+let initials = `${firstName.charAt(0)}${middleName.charAt(0)}${lastName.charAt(0)}`;
+console.log(initials);
+console.log(typeof initials);
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn
 
+// I used the mdn documentation to know how to get the first character of a string.
+// I used charAt() method that takes the index of a string and return the character of it.

Sprint-1/1-key-exercises/3-paths.js

@@ -11,13 +11,18 @@
 
 const filePath = "/Users/mitch/cyf/Module-JS1/week-1/interpret/file.txt";
 const lastSlashIndex = filePath.lastIndexOf("/");
-const base = filePath.slice(lastSlashIndex + 1);
+const base = filePath.slice(-8);
 console.log(`The base part of ${filePath} is ${base}`);
 
 // Create a variable to store the dir part of the filePath variable
 // Create a variable to store the ext part of the variable
 
-const dir = ;
-const ext = ;
+const dir = filePath.slice(0, -8);
+const ext = filePath.slice(filePath.length-3);
 
-// https://www.google.com/search?q=slice+mdn
+console.log(`the dir part of filePath variable is ${dir}`);
+console.log(ext);
+
+// https://www.google.com/search?q=slice+mdn
+
+// After studying the slice() method I was able to do this task easily.

Sprint-1/1-key-exercises/4-random.js

@@ -2,8 +2,14 @@ const minimum = 1;
 const maximum = 100;
 
 const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
+console.log(num);
 
 // In this exercise, you will need to work out what num represents?
 // Try breaking down the expression and using documentation to explain what it means
 // It will help to think about the order in which expressions are evaluated
 // Try logging the value of num and running the program several times to build an idea of what the program is doing
+
+// num is a variable that will be assigned an integer number after the operators are done.
+// Math.floor() rounds a decimal to its nearest number to make it an integer. ex = 1.2 => 1.
+// Math.random() is a method used to create numbers between (0-1) and usually it creates a decimal like (0,2) or etc.
+// each time I run it, I got different number as Math.random() generates different number each time we run it.

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

@@ -1,2 +1,8 @@
+
 This is just an instruction for the first activity - but it is just for human consumption
-We don't want the computer to run these 2 lines - how can we solve this problem?
+We don't want the computer to run these 2 lines - how can we solve this problem?
+
+//solution: Simply comment the lines.
+// 1- single line comment like: // example ...
+// 2- multiline comment like : /* a, b, c */
+// comments are for instruction of guidance of who will read our codes, but the computer wont read them.

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

@@ -1,4 +1,10 @@
 // trying to create an age variable and then reassign the value by 1
 
 const age = 33;
-age = age + 1;
+//age = age + 1;
+
+// we can't do that with const variable, because JS locks the reference. 
+// the best choice is to use "let" variable.
+let age2 = 33;
+age2 = age2 + 1; // or age++ if wanna increase by "1";
+console.log(age2);

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

@@ -1,5 +1,9 @@
 // Currently trying to print the string "I was born in Bolton" but it isn't working...
 // what's the error ?
 
-console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+console.log(`I was born in ${cityOfBirth}`);
+        //const cityOfBirth = "Bolton";
+
+// the problem is that our variable is not declared when we print it.
+// to make it work, we should declare our "cityOfBirth" variable before we print it.

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

@@ -1,5 +1,14 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+//const last4Digits = cardNumber.slice(-4);
+let str = cardNumber.toString().slice(-4);
+const last4Digits = Number(str);
+console.log(`${last4Digits} is the last 4 digits of ${cardNumber}`);
+
+//console.log(typeof last4Digits);
+
+// 1- the code is not working because 'slice()' method is not working with numbers.
+// 2- it gives "type error" cardNumber.slice is not a function.
+// 3- my prediction was correct as I studied the slice method and knew it.
 
 // The last4Digits variable should store the last 4 digits of cardNumber
 // However, the code isn't working

Sprint-1/2-mandatory-errors/4.js

@@ -1,2 +1,12 @@
+/*
 const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+const 24hourClockTime = "08:53";
+*/
+// As far as I know we can not start a variable name with a number in JS.
+// Therefore these variables throw error.
+// we can start the name of a variable with letters a-z, A-Z, _ ,and $ . 
+// This is how we correctly name our variables:
+const twelveHourClockTime = "20:53";
+const twenty4HourClockTime = "08:53";
+console.log(`Twelve-hour clock: ${twelveHourClockTime}`);
+console.log(`24-hour clock: ${twenty4HourClockTime}`);

Sprint-1/3-mandatory-interpret/1-percentage-change.js

@@ -2,7 +2,7 @@ let carPrice = "10,000";
 let priceAfterOneYear = "8,543";
 
 carPrice = Number(carPrice.replaceAll(",", ""));
-priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ""));
+priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", ""));
 
 const priceDifference = carPrice - priceAfterOneYear;
 const percentageChange = (priceDifference / carPrice) * 100;
@@ -12,11 +12,13 @@ console.log(`The percentage change is ${percentageChange}`);
 // Read the code and then answer the questions below
 
 // a) How many function calls are there in this file? Write down all the lines where a function call is made
-
+    // line: 4 and line 5 and it is replaceAll().
 // b) Run the code and identify the line where the error is coming from - why is this error occurring? How can you fix this problem?
-
+    // error is coming from line 5. The error is because of not putting comma between the inputs of replaceAll function. 
+    // To fix the problem just add a comma between the inputs of replaceAll function.
 // c) Identify all the lines that are variable reassignment statements
-
+    // Line 4 and 5.
 // d) Identify all the lines that are variable declarations
-
+    // we have variable declarations at lines 1, 2, 7 and 8.
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+    // the purpose of that expression is to turn into number the string and replace all commas  with an empty space.

Sprint-1/3-mandatory-interpret/2-time-format.js

@@ -1,4 +1,4 @@
-const movieLength = 8784; // length of movie in seconds
+const movieLength = 8724; // length of movie in seconds
 
 const remainingSeconds = movieLength % 60;
 const totalMinutes = (movieLength - remainingSeconds) / 60;
@@ -12,14 +12,17 @@ console.log(result);
 // For the piece of code above, read the code and then answer the following questions
 
 // a) How many variable declarations are there in this program?
-
+    // we have 6 variable declarations.
 // b) How many function calls are there?
-
+    // here we have only one which is console.log().
 // c) Using documentation, explain what the expression movieLength % 60 represents
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
-
+    // Remainder operator (%), returns the leftover when one operand divided by the other operand.
+    // movieLength % 60 expression represents the remaining seconds.
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
-
+    // that expression turns the seconds into minutes.
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
-
+    // the result variable represents the movie length in Hour, minutes and seconds.
+    // a better name can be "movieLength".
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+    // as I changed the value of the movieLength the results has changed too.It means this code works with any value.

Sprint-1/3-mandatory-interpret/3-to-pounds.js

@@ -1,21 +1,16 @@
 const penceString = "399p";
 
-const penceStringWithoutTrailingP = penceString.substring(
-  0,
-  penceString.length - 1
-);
+const penceStringWithoutTrailingP = 
+penceString.substring(0, penceString.length - 1); // => "399";
 
-const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
-const pounds = paddedPenceNumberString.substring(
-  0,
-  paddedPenceNumberString.length - 2
-);
+const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0"); // => "399";
+const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2); // => "3"
 
 const pence = paddedPenceNumberString
-  .substring(paddedPenceNumberString.length - 2)
-  .padEnd(2, "0");
+  .substring(paddedPenceNumberString.length - 2) // => "99"
+  .padEnd(2, "0"); 
 
-console.log(`£${pounds}.${pence}`);
+console.log(`£${pounds}.${pence}`); // => "3.99"
 
 // This program takes a string representing a price in pence
 // The program then builds up a string representing the price in pounds
@@ -24,4 +19,12 @@ console.log(`£${pounds}.${pence}`);
 // Try and describe the purpose / rationale behind each step
 
 // To begin, we can start with
-// 1. const penceString = "399p": initialises a string variable with the value "399p"
+// 1. const penceString = "399p": initializes a string variable with the value "399p"
+// 2. const penceStringWithoutTrailingP uses the substring()method to remove the last character.
+// 3. const paddedPenceNumberString tries to add "0" at the beginning, but the length is already 3; so it does nothing.
+// Its worthy to talk about padStart() method. we use this to add a character at the beginning of a string.
+// 4. const pound uses the substring() method on paddedPenceNumberString variable and remove its last two characters.Its value ll be "3".
+// 5. const pence uses substring() on paddedPenceNumberString variable and take its length and then subtract it with 2 ...
+// which will remain like this .substring(1), so it take the index 1 till the last which is only one more index that its character is 9 ...
+// so the final value ll be "99". then uses padEnd( 2, "0") that can not add "0" at the end, as we set the length "2".
+// 6. Lastly, we print the value of our pound and pence variable. which is "3.99".

Sprint-1/4-stretch-explore/chrome.md

@@ -12,7 +12,12 @@ invoke the function `alert` with an input string of `"Hello world!"`;
 
 What effect does calling the `alert` function have?
 
+`answer` // there ll be a pop-up box showing a message and ask us to press ok in order to get rid of it.
+
 Now try invoking the function `prompt` with a string input of `"What is your name?"` - store the return value of your call to `prompt` in an variable called `myName`.
 
 What effect does calling the `prompt` function have?
+`answer` // Here we also have a pop-up box with an input, and it asks the user to type something.
+
 What is the return value of `prompt`?
+`answer` // if the user type something it returns `string` if the user cancel it then it return `null`.

Sprint-1/4-stretch-explore/objects.md

@@ -13,4 +13,11 @@ Try also entering `typeof console`
 Answer the following questions:
 
 What does `console` store?
+
+`Answer` => console stores methods(function) that you can call to      perform actions like logging, warning, or displaying error.
+
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+
+`console.log()` prints the out put.
+`console.assert()` checks the condition.
+`The dot operator` is called member access. It accesses a property or method of an object.

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

@@ -1,13 +1,25 @@
 // Predict and explain first...
-//  =============> write your prediction here
+//  =============> write your prediction here 
+  // `My prediction` => The capitalise function tries to capitalize the first character of the string and concat it with the rest. This function may not run as it has error.
 
 // call the function capitalise with a string input
+  // `I called the capitalise function and found out there is a syntax error, we have already declared our 'str' variable in our function parameter, so its not a good idea to declare the same variable name as it ll throw an error.`
+
 // interpret the error message and figure out why an error is occurring
+  // `The error occurs because we have declared the same (str) variable two times`. We can not declare two variables with the same name.
 
-function capitalise(str) {
+/*function capitalise(str) {
   let str = `${str[0].toUpperCase()}${str.slice(1)}`;
   return str;
 }
+console.log(capitalise("Roman"));*/
 
 // =============> write your explanation here
+  // `to make this function run we should make we should declare two different variables in our function
+  // .one as a parameter of the func and assign it with the above value. the second option is to return directly without creating a variable.`
 // =============> write your new code here
+function capitalized(str2){
+  let capitalizedStr = `${str2[0].toUpperCase()}${str2.slice(1)}`;
+  return capitalizedStr;
+}
+console.log(capitalized("hi dear"));

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

@@ -1,20 +1,26 @@
 // Predict and explain first...
+// =====> This function tries to convert a decimal number to percentage, but I think it will not run as we have declared same variable name two times.
 
 // Why will an error occur when this program runs?
-// =============> write your prediction here
+// =============> It will throw an error as we have declared decimalNumber variable in our function parameter and again we declared this decimalNumber variable inside our function.
 
 // Try playing computer with the example to work out what is going on
 
-function convertToPercentage(decimalNumber) {
+/*function convertToPercentage(decimalNumber) {
   const decimalNumber = 0.5;
   const percentage = `${decimalNumber * 100}%`;
 
   return percentage;
 }
+console.log(decimalNumber);*/
 
-console.log(decimalNumber);
-
-// =============> write your explanation here
+// =============> I tried to run this, it throw an error like: 'decimalNumber' has already been declared. to fix this we should remove the decimalNumber variable which we have inside our function.
 
 // Finally, correct the code to fix the problem
 // =============> write your new code here
+function convertToPercentage(decimalNumber) {
+  const percentage = `${decimalNumber * 100}%`;
+  console.log(`Your Decimal number will be ${percentage}.`);
+  return percentage;
+}
+convertToPercentage(0.9);

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

@@ -1,20 +1,27 @@
 
 // Predict and explain first BEFORE you run any code...
+// ====> As my understanding this function will throw and error as we have have not called the function with the argument 'num' .
 
-// this function should square any number but instead we're going to get an error
+// this function should square any number but instead we're going to get an error.
+// ====> it will not square any number but 3 when we call it with the argument 'num' inside.
 
-// =============> write your prediction of the error here
 
-function square(3) {
+/*function square(3) {
     return num * num;
-}
+}*/
 
 // =============> write the error message here
+// the error message is: SyntaxError: Unexpected number.
 
 // =============> explain this error message here
+// after running I understood that we can not put a value in function parameter but a variable name. to make it short, in JavaScript we put variable in parameter and value as argument when calling the function.
 
 // 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

@@ -1,14 +1,20 @@
 // Predict and explain first...
 
-// =============> write your prediction here
+// =============> This function will not execute any operation, as it does not return anything.
 
-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)}`);
+// console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
 
 // =============> write your explanation here
+// After running the code, I found that the function works partially, it prints lines 6 and as we called the function on line 9. but line 9 has an error to be fixed. As it does not print what we need.
+// also : In JavaScript, if a function doesn’t explicitly return something, it automatically returns. this is why we have got the first input ok and the second input Undefined.
 
 // Finally, correct the code to fix the problem
-//  =============> write your new code here
+//  =============> 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 +1,17 @@
 // Predict and explain first...
-//  =============> write your prediction here
+//  =============> This function will not return the sum of a + b as the operation is located on the next line or return. so we ll have a syntax error.
 
-function sum(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)}`);
+// =============> after running the code I got undefined on the output as our function does not return anything. because after return keyword our function do not operate the codes.
 
-// =============> write your explanation here
 // 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)}`);