ITP-JAN 2025 | London | ELVIRA MLADENOVA | MODULE-STRUCTURING AND TESTING DATA | Week 4 | Sprint1

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
+
+// Line 3 is updating the value (count)
+//The left-hand side (count) is the variable being assigned a value,while = is the assignment operation.
+//The = operator assigns the new value (1) to the count variable, replacing the old value (0).
+//Now, count stores 1

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

@@ -5,7 +5,8 @@ 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[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 +17,10 @@ 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 lastDotIndex = base.lastIndexOf(".");
+const dir = filePath.slice(0, lastSlashIndex);
+const ext = base.slice(lastDotIndex);
+console.log("The directory 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

@@ -7,3 +7,17 @@ const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
 // 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
+
+console.log(num)
+//num represent a random integer between 1 and 100
+//1. Math.random() generates a random decimal number between  0  and 1
+
+//2. maximum - minimum + 1 calculates the  numbers we want to generate.
+// In this case, 100 - 1 + 1 = 100, so the range is 100.
+
+//3. Math.floor() rounds the number down to the nearest whole number.
+//This ensures we get an integer between 0 and 99
+
+//4. + minimum
+//Adding minimum (which is 1) shifts the range from [0, 99] to [1, 100].
+//This means num is now a whole number between 1 and 100

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

@@ -1,2 +1,5 @@
 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?
+
+ //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 +2,7 @@
 
 const age = 33;
 age = age + 1;
+
+let age = 33
+age += 1
+console.log(age);

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

@@ -3,3 +3,8 @@
 
 console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+
+The code brings the error “cityOfBirth is not defined” because the cityOfBirth is used before it is defined.Line 5 should come before line 4 to have the proper result.
+
+const cityOfBirth = "Bolton";
+console.log(`I was born in ${cityOfBirth}`);

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

@@ -7,3 +7,12 @@ const last4Digits = cardNumber.slice(-4);
 // 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
+
+//It is not working because we can not use "slice method " with numbers only with strings and arrays.
+//In this case we have number.We should turn the number to string in order to work.
+
+
+//solution:
+const cardNumber = 4533787178994213;
+const last4Digits = cardNumber.toString().slice(-4);
+console.log(last4Digits);

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

@@ -1,2 +1,7 @@
 const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+const 24hourClockTime = "08:53";
+
+//Variable names cannot start with a number in JavaScript.And the input is not at the correct time.
+//corrected:
+const hourClockTime24 = "20:53";
+const hourClockTime12 = "08:53";

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

@@ -12,11 +12,25 @@ 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 function calls:Line 4 → replaceAll(",", "")
+//Line 4 → Number()
+//Line 6 → replaceAll(",", "") 
+//Line 6 → Number()
+//Line 10 → console.log()
 
 // 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?
+//The error is on line 5:priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ""));
+//The function call replaceAll(",", "") is incorrect because there is an extra double quote inside replaceAll(), making it invalid syntax.
+//The correct syntax is:priceAfterOneYear.replaceAll(",", "")
 
 // c) Identify all the lines that are variable reassignment statements
+//line 4:carPrice = Number(carPrice.replaceAll(",", "")); and line 5: priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", ""));
+
 
 // d) Identify all the lines that are variable declarations
+// line 1:let carPrice = "10,000"; line 2:let priceAfterOneYear = "8,543"; line 7: const priceDifference = carPrice - priceAfterOneYear;
+//line 8:const percentageChange = (priceDifference / carPrice) * 100;
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+//carPrice.replaceAll(",", "") -This removes all commas from the carPrice string.Number() converts string into a number.
+//The purpose of Number(carPrice.replaceAll(",", "")) is to convert a string representing a price into a numerical value that can be used for calculations.

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

@@ -12,14 +12,24 @@ 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 variable declarations: Line 1,3,4,6,7,9
 
 // b) How many function calls are there?
+// 1 function call → console.log(result);
 
 // c) Using documentation, explain what the expression movieLength % 60 represents
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
+//In this program, movieLength % 60 is used to extract the remaining seconds after calculating the total number of complete minutes in the movie.
+//The expression movieLength % 60 uses the modulus operator (%) to compute the remainder when movieLength (in seconds) is divided by 60.
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+//const totalMinutes = (movieLength - remainingSeconds) / 60;-The expression (movieLength - remainingSeconds) / 60 calculates the total number of complete minutes in the movie, excluding any leftover seconds.
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+//The variable result represents the formatted time of the movie in the (hours:minutes:seconds)format.Represents the total duration of the movie
+//Better name: movieTime
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+//For small and medium-sized movie lengths, the code works well- converting seconds to a properly formatted HH:MM:SS string.
+//For negative movieLength values, the code could give incorrect results-If movieLength is negative (e.g., -1000), the modulus (%) operator and division will still function mathematically, but the results may not make sense in the context of time.
+//If movieLength is extremely large, like movieLength = 99999999 seconds, the code will still work, but the output will be impractical 

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

@@ -24,4 +24,16 @@ 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": initialises a string variable with the value "399p".We need to store this value to work with it in the following steps.
+//3. const penceStringWithoutTrailingP = penceString.substring(0, penceString.length - 1);-This line removes the  "p" from the penceString using the substring method.
+//We want to work only with the numeric part of the string, so we remove the "p" character at the end of the string ("399" from "399p").
+//8. const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");-This line ensures that the string representing pence is at least 3 characters long, padding it with leading zeros if necessary.
+// This step ensures that even if the number of pence is less than 100, we can still treat it as having 2 digits, like "009".
+//9. const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2);-This line extracts the pounds part from the paddedPenceNumberString. It takes the first part of the string before the last two digits, which represent the pence.
+// We want to separate the pounds from the pence. Since we have padded the pence number to 3 digits , this operation takes everything except the last two digits,which represent the pence.
+//14. const pence = paddedPenceNumberString
+ // .substring(paddedPenceNumberString.length - 2)
+// .padEnd(2, "0");- This line extracts the pence part from the string and ensures it is exactly two digits long by adding  zeros if needed.
+// The substring(paddedPenceNumberString.length - 2) extracts the last two digits  from the padded string. Then, .padEnd(2, "0") ensures that if the number of pence is less than 10 it will be padded to two digits.
+//18. console.log(`£${pounds}.${pence}`);-This line formats the output into a readable string representing pounds and pence, then prints it to the console.
+// We now have two parts of the value—pounds and pence—and we need to combine them into a string that represents the value in a human-readable format. This line creates a string in the format £X.XX where X is the respective number of pounds and pence, and prints it.