Scotland | ITP-May-2025 | Nataliia Volkova | Module-Structuring-and-Testing-Data/Coursework/sprint 1

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

@@ -4,3 +4,8 @@ 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
+
+// Answer:
+
+// Line 3 takes the current variable count with a value, that was initially assigned to 0 and then adds 1 to it.
+// Then store result back in the same variable.

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

@@ -5,7 +5,13 @@ 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 = ``;
+// Answer:
 
-// https://www.google.com/search?q=get+first+character+of+string+mdn
+// There are two ways to access an individual character in a string. The first is the charAt() method. Another -
+// is to treat the string as an array-like object, where individual characters correspond to a numerical index.
+// I choose the second one.
+
+let initials = firstName[0] + middleName[0] + lastName[0];
+console.log(initials);
 
+// https://www.google.com/search?q=get+first+character+of+string+mdn

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

@@ -17,7 +17,11 @@ 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, lastSlashIndex);
 
-// https://www.google.com/search?q=slice+mdn
+const lastDotIndex = filePath.lastIndexOf(".");
+const ext = filePath.slice(lastDotIndex + 1);
+console.log(`The dir part of ${filePath} is ${dir}`);
+console.log(`The extension part of ${filePath} is ${ext}`);
+
+// https://www.google.com/search?q=slice+mdn

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

@@ -2,8 +2,18 @@ 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
+
+// 1st Step Math.random() to generate random number between 0 and 1.
+// 2nd Step is (maximum - minimum + 1)
+// 3d Step is Math.random() * (maximum - minimum + 1)
+// 4th Step is Math.floor(Math.random() * (maximum - minimum + 1))
+// 5th Step is Math.floor(Math.random() * (maximum - minimum + 1)) + minimum
+// This is about simulating random numbers. Useful for quizzes, games, for anything that needs random choice.
+// Math.floor() to round float number to the greatest than or equal integer.
+// + minimum in this case 1, to make the random possible choice real one, not 0.

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

@@ -1,2 +1,2 @@
-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?
+// 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?

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

@@ -2,3 +2,6 @@
 
 const age = 33;
 age = age + 1;
+
+// This is not possible because the variable is const type, so immutable.
+// TypeErrore: Assignment to constant variable.

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

@@ -3,3 +3,6 @@
 
 console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+
+// That is because the console.log is going first than variable which even doesn't exist.
+// Causes a ReferenceError.

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

@@ -1,9 +1,13 @@
-const cardNumber = 4533787178994213;
+const cardNumber = `4533787178994213`;
 const last4Digits = cardNumber.slice(-4);
+console.log(last4Digits);
 
 // The last4Digits variable should store the last 4 digits of cardNumber
 // However, the code isn't working
 // Before running the code, make and explain a prediction about why the code won't work
 // Then run the code and see what error it gives.
 // Consider: Why does it give this error? Is this what I predicted? If not, what's different?
 // Then try updating the expression last4Digits is assigned to, in order to get the correct value
+
+// My prediction: the code is not working because cardNumber variable contains numbers but not string.
+// TypeError: ReferenceError

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

@@ -1,2 +1,8 @@
-const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+const HourClockTime = "20:53";
+const hourClockTime = "08:53";
+
+// Mistake is that the variables' name start with number.
+// There are some rules how to name variables:
+// 1.Name shouldn't start with number.
+// 2.Variable name shouldn't contain any spacial characters or spaces.
+// 3.Variable name shouldn't be a specific key word.

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 +12,17 @@ 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
+// 5
 
 // 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?
+// SyntaxError: missing "","" after argument list Line: 5
 
 // c) Identify all the lines that are variable reassignment statements
+// Lines: 4 and 5
 
 // d) Identify all the lines that are variable declarations
+// Lines: 1, 2, 7, 8
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+// The Number function changes the type of value from string to number. carPrice.replaceAll(",","") replaces all
+// comas in string on space.

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

@@ -12,14 +12,23 @@ 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?
+// 6
 
 // b) How many function calls are there?
+// 1
 
 // c) Using documentation, explain what the expression movieLength % 60 represents
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
+// The remainder (%) operator returns the remainder left over when one operand is divided
+// by a second operand. It always takes the sign of the dividend. 8784 % 60 = 24 It calculates the leftover
+// seconds after full minutes are taken out.
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+// const totalMinutes = (movieLength - remainingSeconds) / 60;
+// TotalMinutes means movie length in seconds minus remaining seconds and transforms it into minutes.
 
-// e) What do you think the variable result represents? Can you think of a better name for this variable?
+// e) What do you think the variable result represents? It represent time in the format: HH.MM.SS
+// The variable Result has a too general name. I would rename it. Foe example, FormattingTime
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+// It works well for integers. Doesn't work for negative numbers and strings. Unless we convert them. for 0 it gives 0:0:0

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

@@ -24,4 +24,27 @@ 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: give a string variable  without the last character, "p".
+// We use the method substring to get under 0-index string character as `a start-parameter` of substring and inside the substring function
+// calling function (penceString.length - 1) to get `the end` parameter of substring. As a result, we got `399` without `p`.
+
+// 3. const paddedPenceNumberString: the padStart method pads 0 of the start nceStringWithoutTrailingP variable until
+// it becomes a 3-character length.
+
+// 4. const pounds: give a string variable  without the last 2 characters, "99".
+// We use the method substring to get under 0-index string character as `a start-parameter` of substring and inside the substring
+// calling function (paddedPenceNumberString.length - 2) to get `the end` parameter of substring (not included).
+// As a result, we got `3` without `99`.
+
+// 5. const pence:
+// - .substring(0, paddedPenceNumberString.length - 2) to substring the last two string characters "99" from "399"
+// length -2  of "399" is "3", "3-2=1", so under index `0` as `a start-parameter` we have figure 3 and under index `1`as
+// `the end parameter` we have `9`(not included), As a result, we subtracted everything except "99".
+// - .padEnd(2, "0") We use the method padEnd to get at least 2 characters by adding "0" at the end of our string. S0 we get 99.
+
+// 6. console.log(`£${pounds}.${pence}`): to return the final price we use two gotten variables above and before them
+// £ sign and dot between them. As a result, we have: "£3.99" string.
+
+// In summary, the described step-by-step small program above gives output price in pounds and pence.

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

@@ -12,7 +12,16 @@ invoke the function `alert` with an input string of `"Hello world!"`;
 
 What effect does calling the `alert` function have?
 
+My answer: it opens a popup alert-box chrome://new-tab-page-says in the browser with a message Hello world!, and it is not going to be disappear until press buttons "ok" or "cancel".
+
 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`.
 
+My answer: let myName = prompt("What is your name?")
+
 What effect does calling the `prompt` function have?
+
+My answer: it invokes the popup box chrome:// new-page-says and an input field for user to enter his name. User prompt to enter his name and press "ok" or "cancel", then box disappear.
+
 What is the return value of `prompt`?
+
+My answer: return some string typed by user or Null if the user press button "cancel".

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

@@ -6,11 +6,18 @@ Open the Chrome devtools Console, type in `console.log` and then hit enter
 
 What output do you get?
 
+My answer: Undefined
+
 Now enter just `console` in the Console, what output do you get back?
 
 Try also entering `typeof console`
 
-Answer the following questions:
+Answer the following questions: built-in 'object' in Console developer environment on Chrome V8.
 
 What does `console` store?
+
+My answer: console {debug: ƒ, error: ƒ, info: ƒ, log: ƒ, warn: ƒ, …} The object `console` stores a list of logging and debugging functions.
+
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+
+My answer: .log and .assert are methods(functions) attached to object `console`. The "." (dot) is a operator or member operator. `console.log` inspect variables, debug code. `console.assert` test condition. If the condition is False, it log a message about error. If Tru, it records nothing(console.log(condition, message)).