Sheffield | May-2025 | Hassan Osman | Sprint-1

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

@@ -4,3 +4,9 @@ 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 shows increment operation - the variable count gets reassigned a new value which is the sum of the old value and 1.
+In other words, the variable count is now adding 1 to its old value to obtain a new value.
+*/
+

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

@@ -5,7 +5,7 @@ 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)}`;
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn
 

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

@@ -17,7 +17,7 @@ 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(1,lastSlashIndex);
+const ext = filePath.slice(filePath.indexOf("."));
 
 // https://www.google.com/search?q=slice+mdn

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

@@ -7,3 +7,11 @@ 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
+
+/* 
+1. Since Math.random() returns an integer in the interval [0, 1). This means num eventually represents any random integer in the interval [0, 100]. 
+2. Math.floor() rounds down the expression "Math.random() * (maximum - minimum + 1)"", leading to an integer in the interval [0,100).
+
+3. So num returns an integer in the interval [0,100) + 1 which eventually means num return [0, 100]
+4. Done!
+*/

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

@@ -1,2 +1,17 @@
 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? 
+
+/* 
+I got "SyntaxError: Unexpected identifier" error message. It happen because the 2 lines don't make sense.
+the computor sees the first word and it assumes a variable or a function is being declared but then when 
+it reads the resut of the sentence it breaks as this is not how an identifier is being used and formed in 
+a programme.
+To avoid this issue, we can just simply comment the 2 lines, just like what I am doing here! 
+
+*/
+
+/* 
+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 +2,15 @@
 
 const age = 33;
 age = age + 1;
+
+/*
+I got this error message "TypeError: Assignment to constant variable." after running 
+my code. It happened because when assigned a value to an identifer using const -short 
+for constant - it emplies that we have no intention of changing the value. it remains 
+constant. the second line the variable get reassigned a new value and therefore the 
+error message above showed up.
+To solve this issue the variable age could simply be declared via "let" as seen below:
+*/
+
+let age = 33;
+age = age + 1;

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

@@ -3,3 +3,15 @@
 
 console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+
+/* 
+The error message "ReferenceError: Cannot access 'cityOfBirth' before initialization
+    at Object.<anonymous> " comes up because when the computor reads the first line it 
+    recognised that cityOfbirth is an identifer however it get confused as it has not
+    been declaed beforehand and runs into an error as a result. To overcome this issue
+     and access cityOfBirth, simply declare it in the 1st line and then in the 2nd line 
+     use console.log() to display its value to the terminal as seen below:
+*/
+
+const cityOfBirth = "Bolton";
+console.log(`I was born in ${cityOfBirth}`);

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

@@ -1,9 +1,18 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+//const last4Digits = cardNumber.slice(-4); 
 
 // 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
+
+
+/*
+This error message was thrown after running the code "TypeError: cardNumber.slice is not a function".
+It simply happned because ".slice()" is not a method associated with integers but strings & arrays.
+To avoid this issue the value of last4Digits should be as below:
+*/
+
+const last4Digits = cardNumber.toString().slice(-4);

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

@@ -1,2 +1,7 @@
-const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+//const 12HourClockTime = "20:53";
+//const 24hourClockTime = "08:53";
+
+// to avoid the syntax error after running the above lines of code do as below:
+
+const clockTime24Hour = "20:53";
+const clockTime12Hour = "08:53";

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;
@@ -20,3 +20,17 @@ console.log(`The percentage change is ${percentageChange}`);
 // d) Identify all the lines that are variable declarations
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+
+/*
+a) There are 5 at: 1)carPrice = Number(carPrice.replaceAll(",", "")); & 2)priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," "")),
+3) & 4) const priceDifference = carPrice - priceAfterOneYear; 5) const percentageChange = (priceDifference / carPrice) * 100;
+
+b) The error happened due to the missing comma "," in between the 2 parameters/arguments in line 5's function call. Just add a comma to solve
+this problem.
+
+c) line 4 & line 5
+
+d) lines 1, 2, 7 & 8
+
+e) Firstly, it removes all commas in the string and eventually converts the new string into a number. 
+*/

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

@@ -1,4 +1,4 @@
-const movieLength = 8784; // length of movie in seconds
+const movieLength = 0; // length of movie in seconds
 
 const remainingSeconds = movieLength % 60;
 const totalMinutes = (movieLength - remainingSeconds) / 60;
@@ -23,3 +23,13 @@ console.log(result);
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+
+
+/*
+a) There are 6 in total.
+b) Only one function call "console.log(result)".
+c) it represents the remainder from the division of movieLength by 60.
+d) line 4 represents the total number of mins in the movie (as whole numbers -integers) by getting rid of the decimal parts (in secs).
+e) Result represents the total movie duration (in exact hours, exact min and exact sec). movieDuration could be a good name.
+f) Yes, It does work when trying different values of movieLength.
+*/

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

@@ -25,3 +25,9 @@ console.log(`£${pounds}.${pence}`);
 
 // To begin, we can start with
 // 1. const penceString = "399p": initialises a string variable with the value "399p"
+// 2. ine lines 3-6, penceStringWithoutTrailingP is being declared to get rid of the "p" part of "399p" so that you end up with "399" ONLY.
+// 3. Lines 8 paddedPenceNumberString adds "0" to the start of paddedPenceNumberString which is "399" with the aim of it have a total length of 3.
+// 4. Lines 9-12, pound is being declared, the value of it aims to extract the "full pounds part" considering 1 pound = 1-- pence.
+// 4. Lines 14-16, extract the "pence part" fraction
+// 5. Line 18 prints out the sum in pounds and pense.
+

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?
+// a message with Hello world! message pops up in a small Chrome notification window 
 
 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`.
+// small Chrome window pops up with "What is your name?" and underneath it a space for the user to enter and submit their name.
 
 What effect does calling the `prompt` function have?
+//prompt expect input from the user by showing a small window with space for input to be submitted once called.
 What is the return value of `prompt`?
+//a string - the name entered my the user.

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

@@ -4,13 +4,19 @@ 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?
+What output do you get? 
+//ƒ log() { [native code] }
 
 Now enter just `console` in the Console, what output do you get back?
+// console {debug: ƒ, error: ƒ, info: ƒ, log: ƒ, warn: ƒ, …}
 
 Try also entering `typeof console`
+// got 'object' as an output
 
 Answer the following questions:
 
 What does `console` store?
+//it stores different logging, debugging, warning/errors and information properties.
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+//console.log log or display values to the console. Console.assert, check if a condition is true and in this case no output. Otherwise, an
+// error message shows. As for the `,`, it's called the dot notation and it's used to access properties and methods of an object.