Glasgow | 26-ITP-May | Niangh Ciang | Sprint 1 | Coursework Exercises

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

@@ -2,5 +2,4 @@ let count = 0;
 
 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 takes the current value of count, adds 1 to it, and then uses the = operator to assign (store) the new value back into the count variable.

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

@@ -2,10 +2,5 @@ let firstName = "Creola";
 let middleName = "Katherine";
 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 = ``;
-
-// https://www.google.com/search?q=get+first+character+of+string+mdn
-
+let initials = firstName[0] + middleName[0] + lastName[0];
+console.log(initials);

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

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

@@ -4,6 +4,13 @@ const maximum = 100;
 const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
 
 // In this exercise, you will need to work out what num represents?
+//num is a random whole number between the minimum and maximum values.
+
 // Try breaking down the expression and using documentation to explain what it means
+// Math.random() generates a random number that's greater than or equal to 0 and less than 1
+// Math.floor() rounds a number down to the nearest whole number
+
 // 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);
+//I have run it several times and I saw that the number is changing each time.

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

@@ -1,4 +1,6 @@
 // trying to create an age variable and then reassign the value by 1
 
-const age = 33;
+let age = 33;
 age = age + 1;
+
+console.log(age);

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

@@ -1,5 +1,7 @@
 // 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}`);
+
+//The error is that cityOfBirth is used before it is declared. The console.log runs before the variable exists.

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

@@ -1,9 +1,15 @@
-const cardNumber = 4533787178994213;
+const cardNumber = "4533787178994213";
 const last4Digits = cardNumber.slice(-4);
 
+console.log(`The last 4 digits of the card number are ${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
+
+//When I ran the code I got: TypeError: cardNumber.slice is not a function
+//I understand this happens because .slice() only works on strings, not numbers
+//To fix this I converted the number into a string so .slice() works

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

@@ -1,2 +1,9 @@
-const 12HourClockTime = "8:53pm";
-const 24hourClockTime = "20:53";
+const TwelveHourClockTime = "8:53pm";
+const TwentyFourHourClockTime = "20:53";
+
+console.log(TwelveHourClockTime);
+console.log(TwentyFourHourClockTime);
+
+// The original code caused an error because variable names cannot start with a number.
+// I fixed the error by renaming the variables so they start with letters instead of numbers.
+//The code runs correctly and prints both time formats.

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 +12,19 @@ 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
+// There are 3 function calls in this file.
+// They are on lines 4, 5, 10.
 
 // 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 coming from line 5. This happens because there is a syntax error in the replaceAll function call.
+// I can fix this problem by adding the missing comma between the arguments.
 
 // c) Identify all the lines that are variable reassignment statements
+// The variable reassignment statements are on lines 4 and 5.
 
 // d) Identify all the lines that are variable declarations
+// The variable declarations are on lines 1, 2, 6, and 7.
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+// The expression first removes all commas from the price string.
+// Then converts the cleaned string into a number so it can be used in calculations.

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

@@ -1,4 +1,4 @@
-const movieLength = 8784; // length of movie in seconds
+const movieLength = 4758; // length of movie in seconds
 
 const remainingSeconds = movieLength % 60;
 const totalMinutes = (movieLength - remainingSeconds) / 60;
@@ -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?
+// There are 6 variable declarations in this program. They are on lines 1, 3, 4, 6, 7, and 9.
 
 // b) How many function calls are there?
+// There are 1 function call in this program. It is on line 10.
 
 // c) Using documentation, explain what the expression movieLength % 60 represents
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
+// It represents the remainder when movieLength is divided by 60.
+// This tells us how many seconds are left over after removing all the full minutes using the modulo operator.
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+// totalMinutes is the number of full minutes in the movie after removing the leftover seconds.
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+// It represents the final time format of the movie in hours, minutes, and seconds.
+// A clearer name would be something like movieDuration.
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+// I tried running different numbers and it still works, even when the value is negative.
+// The maths runs, but negative movie lengths don’t make real-world sense, so the output isn’t meaningful.

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

@@ -1,20 +1,26 @@
+//initialises a string variable with the value "399p"
 const penceString = "399p";
 
+//Removes the last character "p" from "399p", leaving just "399".
 const penceStringWithoutTrailingP = penceString.substring(
   0,
   penceString.length - 1
 );
 
+//Ensures the pence value has at least 3 digits by adding leading zeros if needed.
 const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+//Takes all but the last two digits as the pounds part
 const pounds = paddedPenceNumberString.substring(
   0,
   paddedPenceNumberString.length - 2
 );
 
+//Takes the last two digits as the pence part and keeps it at 2 digits
 const pence = paddedPenceNumberString
   .substring(paddedPenceNumberString.length - 2)
   .padEnd(2, "0");
 
+//Prints the final price in pounds format
 console.log(`£${pounds}.${pence}`);
 
 // This program takes a string representing a price in pence

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

@@ -11,8 +11,12 @@ In the Chrome console,
 invoke the function `alert` with an input string of `"Hello world!"`;
 
 What effect does calling the `alert` function have?
+Calling alert("Hello world!") shows a dialogue window with the message "Hello world!".
 
 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?
 What is the return value of `prompt`?
+Calling prompt("What is your name?") shows a dialog box with a text field.
+It asks the user for input and returns whatever the user types as a string.
+If the user clicks Cancel, the return value is null.

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

@@ -5,12 +5,18 @@ In this activity, we'll explore some additional concepts that you'll encounter i
 Open the Chrome devtools Console, type in `console.log` and then hit enter
 
 What output do you get?
+I get the function definition for console.log (function log()).
 
 Now enter just `console` in the Console, what output do you get back?
+I get console {debug: ƒ, error: ƒ, info: ƒ, log: ƒ, warn: ƒ, …}
 
 Try also entering `typeof console`
 
 Answer the following questions:
 
 What does `console` store?
+console stores an object with many functions like log, error, warn, assert.
+
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+console.log or console.assert means we are calling a function inside the console object.
+The dot (.) means “access this property of the object”.