London | 26-ITP-May | Bisrat Tesfay| Sprint 1 | Coursework

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

@@ -2,5 +2,8 @@ let count = 0;
 
 count = count + 1;
 
+console.log(count);
+
 // 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 adds 1 to the current value of count. The = sign means we save the new value back into count. Since count started at 0, count + 1 makes it 1

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

@@ -2,10 +2,10 @@ let firstName = "Creola";
 let middleName = "Katherine";
 let lastName = "Johnson";
 
+let initials = firstName[0] + middleName[0] + lastName[0];
+console.log(initials);
+
 // 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
-

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 dir = filePath.slice(0, lastSlashIndex);
+const ext = filePath.slice(filePath.lastIndexOf("."));
 
-// https://www.google.com/search?q=slice+mdn
+console.log(dir);
+console.log(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 creates a random whole number between 1-100 (inclusive).
 // Try breaking down the expression and using documentation to explain what it means
+//maximum-minimum+1 gives us the number of possible values (100-1+1 = 100)
+//Math.random() gives us a random decimal number between 0 (inclusive) and 1 (exclusive)
+//Multiplying Math.random() by 100 gives us a random decimal number between 0 and 100 (exclusive)
+//Math.floor() rounds down the random decimal number to the nearest whole number.
+//Adding minimum to the result gives us a random whole number between minimum and maximum (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?
+//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?
+//By adding // at the beginning of each line, we can turn them into comments.

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);
+// let can allow us to reassign the value of a variable.

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

@@ -1,5 +1,6 @@
 // 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 the order. JavaScript always reads the code from top to bottom.

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

@@ -1,9 +1,12 @@
-const cardNumber = 4533787178994213;
+const cardNumber = "4533787178994213";
 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
+// First the code doesn't have console.log()to print the value of last four digits. Second, the slice can't be negative.
 // 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?
+// The error is that slice is not a function. This is because cardNumber is a number and slice is a string method. To fix this, we need to convert cardNumber to a string before using slice.
 // Then try updating the expression last4Digits is assigned to, in order to get the correct value
+console.log(last4Digits);

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

@@ -1,2 +1,3 @@
-const 12HourClockTime = "8:53pm";
-const 24hourClockTime = "20:53";
+const twelveHourClockTime = "8:53pm";
+const twentyFourHourClockTime = "20:53";
+//variables can't start with a number. To fix this, we need to change the variable name to something that starts with a letter or an underscore.

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 +12,18 @@ 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 the fourth line Number () and replaceAll ().
+// In the fifth line same as line 4 Number () and replaceAll ().
+// Last one in seventh line 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 in line 5. The error is occurring because there is a missing comma in the replaceAll function. The correct code should be: priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", ""));
 
 // c) Identify all the lines that are variable reassignment statements
+// Line 4 and line 5 are variable reassignment statements. In line 4, carPrice is being reassigned with the new value after removing the comma and converting it to a number. In line 5, priceAfterOneYear is being reassigned in the same way.
 
 // d) Identify all the lines that are variable declarations
+// Line 1 and line 2 are variable declarations. In line 1, carPrice is declared and initialized with the string value "10,000". In line 2, priceAfterOneYear is declared and initialized with the string value "8,543".
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+// The expression removes the comma from the price string and converts it into a number. This allows JavaScript to use the value in calculations.

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

@@ -12,14 +12,22 @@ 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: movieLength, remainingSeconds, totalMinutes, remainingMinutes, totalHours, and result.
 
 // b) How many function calls are there?
+// There is 1 function call in this program: 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
+// The % operator is the remainder operator.
+// It returns the remainder left over after one number is divided by another number.
+// MovieLength % 60 finds the remaining seconds after dividing the total movie length by 60.
+// This is used to calculate how many seconds are left after converting the total seconds into minutes.
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
-
+// Take away the leftover seconds, then convert the rest into minutes.
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
-
+// The movie length displayed as hours:minutes:seconds.
+// A better name for this variable could be movieDuration.
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+// Yes, it works for all movie lengths except for negative and text values.

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

@@ -25,3 +25,18 @@ console.log(`£${pounds}.${pence}`);
 
 // To begin, we can start with
 // 1. const penceString = "399p": initialises a string variable with the value "399p"
+
+// 2. const penceStringWithoutTrailingP = penceString.substring(0, penceString.length - 1):
+// removes the last character ("p") from the string, leaving only the number part "399".
+
+// 3. const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0"):
+// makes sure the pence value has at least 3 characters by adding zeros at the start if needed.
+
+// 4. const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2):
+// takes the first part of the string to get the pounds value.
+
+// 5. const pence = paddedPenceNumberString.substring(paddedPenceNumberString.length - 2).padEnd(2, "0"):
+// takes the last two characters to get the pence value and adds a zero at the end if needed.
+
+// 6. console.log(`£${pounds}.${pence}`):
+// prints the final price in pounds and pence format.

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

@@ -12,7 +12,9 @@ invoke the function `alert` with an input string of `"Hello world!"`;
 
 What effect does calling the `alert` function have?
 
+// A pop up window on the webpage.
 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`?
+//prompt() asks for input, returns the user's answer

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

@@ -13,4 +13,6 @@ Try also entering `typeof console`
 Answer the following questions:
 
 What does `console` store?
+Console stores an object.
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+The dot is used to access something inside an object. console.log means access the log function that is stored inside the console object.