debugged and corrected the errors accordingly.

Author: Yonatanteklemariam

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

@@ -4,3 +4,4 @@ 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 of the count variable by adding 1 to its current value. In other words, it is re-assignining the count variable to be equal to its previous value plus 1. It is called a statement.

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]}`;
 
-// https://www.google.com/search?q=get+first+character+of+string+mdn
+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 +17,9 @@ 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);
+console.log(`The dir part of ${filePath} is ${dir}`);
+const ext = filePath.slice(filePath.lastIndexOf(".") + 1);
+console.log(`The ext part of ${filePath} is ${ext}`);
 
-// https://www.google.com/search?q=slice+mdn
+// https://www.google.com/search?q=slice+mdn

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

@@ -4,6 +4,15 @@ 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 represents a random integer between the minimum and maximum values, inclusive. The expression math.random() picks any decinmal number between 0 and 1, where then it's multiplied by the change of min & max + 1. Then the Math.floor() rounds the number down to the nearest integer and finally the minimum value is added to ensure the result is withn the specified range.
+
 // Try breaking down the expression and using documentation to explain what it means
+/* Math.random() generates a random decimal number between 0 (inclusive) and 1(not inclusive). 
+The expression (maximum - minimum +1) calculates the range of possible values, which is 100 - 1 + 1 = 100.
+Then the result of Math.random() is multiplied by the range, which gives a random decimal number between 0 and 100 (not inclusive).
+Math.floor() rounds the result down to the nearest integer, which gives a random integer between 0 and 99 (inclusive).
+Finally, adding the minimum value of 1 shifts the range up by 1, resulting in a random integer between 1 and 100 (inclusive). */
+
 // 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);

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

@@ -1,2 +1,3 @@
 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?
+// by adding a comment symbol in front of the lines, so that the computer ignores them when running the code.

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

@@ -1,4 +1,7 @@
 // trying to create an age variable and then reassign the value by 1
 
 const age = 33;
-age = age + 1;
+age = age + 1; // this line will cause an error because age is declared as constant and cannot be reassigned.
+
+let age = 33;
+age += 1; // this line will work because age is declared as a variable and can be reassigned.

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

@@ -1,5 +1,5 @@
 // Currently trying to print the string "I was born in Bolton" but it isn't working...
 // what's the error ?
-
+// the error is that the variable cityOfBirth is being used before it is declared.
 console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";

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

@@ -1,9 +1,17 @@
 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
+// The code won't work because cardNumber is a number, and the slice method is a string method. So the cardNumber value needs to be coverted to a string. It can be done by using the cardNumber.toString() method or by using string(cardNumber) method or even by using template literals as shown in the code snippet.
+
 // Then run the code and see what error it gives.
+// The error says cardNumber.slice is not a function. This is becuase the slice method is a string method and cardNumber is a number.
+
 // Consider: Why does it give this error? Is this what I predicted? If not, what's different?
+// At first I thought the error would be that last4Digits is not defined, but I learned that the error is actually because the slice method is being called on a number, which doesn't have that method.
 // Then try updating the expression last4Digits is assigned to, in order to get the correct value
+const last4Digits = cardNumber.toString().slice(-4); // first option
+const last4Digits = String(cardNumber).slice(-4); // second option
+const last4Digits = `${cardNumber}`.slice(-4); // third option

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

@@ -1,2 +1,2 @@
-const 12HourClockTime = "8:53pm";
-const 24hourClockTime = "20:53";
+const 12HourClockTime = "8:53pm"; // this will throw an error because the variable name started with a number where it shouldn't be.
+const 24hourClockTime = "20:53"; // the same happens here as well.

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 +12,27 @@ 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 5 function calls in this code snippet.
+1) carPrice = Number(carPrice.replaceAll(",", "")); --Number(...) & replaceAll(",", "") in this line
+2) priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," "")); --Number(...) & replaceAll("," "") in this line as well.
+3) console.log(`The percentage change is ${percentageChange}`); 
+*/
 
 // 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 shown says ) missing after arguements in the expression of priceAfterOneYear. However when I looked into it carefully, the comma was missing between the arguments, not the ). I also used debugger in vscode and simply pointed out the problem by as on the debug console suggested.
+ */
 
 // c) Identify all the lines that are variable reassignment statements
+/* carPrice = Number(carPrice.replaceAll(",", ""));
+priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", ""));
+*/
 
 // d) Identify all the lines that are variable declarations
+/* let carPrice = "10,000";
+let priceAfterOneYear = "8,543";
+const priceDifference = carPrice - priceAfterOneYear;
+const percentageChange = (priceDifference / carPrice) * 100;
+*/
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+// This expression is coverting the carPrice value by getting rid of the comma in the number and joining the number together. 10,000 ----> 10000