Cape Town | 26-ITP-Sept | Vaidah Simenti | Sprint 2 | Complete Sprint 2 Coursework

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

@@ -1,6 +1,7 @@
-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
+let count = 0;
+
+count = count + 1;
+//Line 1 is variable declaration, creating the count variable with an initial value of 0
+//Line 3 takes the current value of count (0), adds 1 to it (0 + 1 = 1), and uses the assignment operator (=) to reassign and store this new value (1) back into the count variable.
+// 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

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

@@ -1,10 +1,12 @@
-const firstName = "Creola";
-const middleName = "Katherine";
-const 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.
-
-const initials = ``;
-
-// https://www.google.com/search?q=get+first+character+of+string+mdn
+const firstName = "Creola";
+const middleName = "Katherine";
+const 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.
+
+const initials = firstName[0] + middleName[0] + lastName[0];
+
+console.log(initials);
+
+// https://www.google.com/search?q=get+first+character+of+string+mdn

Sprint-2/1-key-exercises/3-paths.js

@@ -1,23 +1,26 @@
-// The diagram below shows the different names for parts of a file path on a Unix operating system
-
-// ┌─────────────────────┬────────────┐
-// │          dir        │    base    │
-// ├──────┬              ├──────┬─────┤
-// │ root │              │ name │ ext │
-// "  /    home/user/dir / file  .txt "
-// └──────┴──────────────┴──────┴─────┘
-
-// (All spaces in the "" line should be ignored. They are purely for formatting.)
-
-const filePath = "/Users/mitch/cyf/Module-JS1/week-1/interpret/file.txt";
-const lastSlashIndex = filePath.lastIndexOf("/");
-const base = filePath.slice(lastSlashIndex + 1);
-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 = ;
-
+// The diagram below shows the different names for parts of a file path on a Unix operating system
+
+// ┌─────────────────────┬────────────┐
+// │          dir        │    base    │
+// ├──────┬              ├──────┬─────┤
+// │ root │              │ name │ ext │
+// "  /    home/user/dir / file  .txt "
+// └──────┴──────────────┴──────┴─────┘
+
+// (All spaces in the "" line should be ignored. They are purely for formatting.)
+
+const filePath = "/Users/mitch/cyf/Module-JS1/week-1/interpret/file.txt";
+const lastSlashIndex = filePath.lastIndexOf("/");
+const base = filePath.slice(lastSlashIndex + 1);
+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 = filePath.slice(0, lastSlashIndex);
+const ext = filePath.slice(filePath.lastIndexOf("."));
+
+console.log(dir);
+console.log(ext);
+
 // https://www.google.com/search?q=slice+mdn

Sprint-2/1-key-exercises/4-random.js

@@ -1,9 +1,27 @@
-const minimum = 1;
-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?
-// 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
+const minimum = 1;
+const maximum = 100;
+
+const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
+
+console.log(num);
+
+// In this exercise, you will need to work out what num represents?
+// 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
+// Breakdown of the expression
+
+// The order is inner brackets first, multiplication, Math.floor and then + minimum
+// 1. maximum - minimum + 1 that is 100 - 1 + 1 = 100
+// This gives the total number of possible values (1 to 100 = 100)
+
+// 2. Math.random() is a random decimal between 0 and 1 but not including 1 like 0.7392..
+//    Math.random()*(maximum - minimum +1) 
+//    0.7392 * 100 = 73.92 
+
+// 3. Math.floor(73.92) = 73 ,
+//    it rounds down to the nearest whole number an integer from 0 to 99
+
+// 4. + minimum will be 73 + 1 = 74
+//    num represents random whole number between 1 and 100  
+

Sprint-2/2-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?
+//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?
+
+   //answer: 1.by adding the 2 forward slashes before every line for single-line comment.
+   //        2.If it is a multi-line comment you wrap the code in a slash-star and slash-star symbols

Sprint-2/2-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;
+// trying to create an age variable and then reassign the value by 1
+
+const age = 33;
+age = age + 1;
+
+// there is a TypeError: Assignment to constant variable, 
+// that tells us that changing a const is not allowed

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

@@ -1,5 +1,11 @@
-// 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";
+// Currently trying to print the string "I was born in Bolton" but it isn't working...
+// what's the error ?
+
+const cityOfBirth = "Bolton";
+console.log(`I was born in ${cityOfBirth}`);
+
+// the error is ReferenceError: Cannot access 'cityOfBirth' before initialization,
+// reason is the console.log was entered before the variable declaration.
+//  Console.log cannot run something that is not there yet.
+// To fix it , move the const declaration above the console.log
+

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

@@ -1,9 +1,10 @@
-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
-// 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
+const cardNumber = "4533787178994213";
+const last4Digits = cardNumber.slice(-4);
+console.log(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

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

@@ -1,2 +1,11 @@
-const 12HourClockTime = "8:53pm";
-const 24hourClockTime = "20:53";
+const twelveHourClockTime = "8:53pm";
+const twentyFourHourClockTime = "20:53";
+
+console.log(twelveHourClockTime);
+console.log(twentyFourHourClockTime);
+
+// Original code used `12HourClockTime` and `24hourClockTime` as variable names.
+// but these start with numbers, which JavaScript doesn't allow 
+// variable names must start with a letter, underscore, or dollar sign.
+// So I renamed them to `twelveHourClockTime` and `twentyFourHourClockTime`.
+// This avoids the SyntaxError and makes the code run.

Sprint-2/3-mandatory-interpret/1-percentage-change.js

@@ -1,22 +1,30 @@
-let carPrice = "10,000";
-let priceAfterOneYear = "8,543";
-
-carPrice = Number(carPrice.replaceAll(",", ""));
-priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ""));
-
-const priceDifference = carPrice - priceAfterOneYear;
-const percentageChange = (priceDifference / carPrice) * 100;
-
-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
-
-// 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?
-
-// c) Identify all the lines that are variable reassignment statements
-
-// 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?
+let carPrice = "10,000";
+let priceAfterOneYear = "8,543";
+
+carPrice = Number(carPrice.replaceAll(",", ""));
+priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ""));
+
+const priceDifference = carPrice - priceAfterOneYear;
+const percentageChange = (priceDifference / carPrice) * 100;
+
+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
+     //answer: we have 5 function calls across 3 lines: 
+     //line 4
+     //line 5
+    //line 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?
+    //answer: on line 5, there is an error caused by a missing comma replaceAll("," ""));. Can be fixed by changing it to priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", ""));
+
+// c) Identify all the lines that are variable reassignment statements
+    //answer: lines 4 and 5
+
+// d) Identify all the lines that are variable declarations
+    //answer: line 1, 2, 7 and 8
+
+// e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+    //answer: .ReplaceAll(",", "") this will remove every comma from the price string and number will convert that clean string into a numeric value so mathematical calculations can be performed.

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

@@ -1,25 +1,31 @@
-const movieLength = 8784; // length of movie in seconds
-
-const remainingSeconds = movieLength % 60;
-const totalMinutes = (movieLength - remainingSeconds) / 60;
-
-const remainingMinutes = totalMinutes % 60;
-const totalHours = (totalMinutes - remainingMinutes) / 60;
-
-const result = `${totalHours}:${remainingMinutes}:${remainingSeconds}`;
-console.log(result);
-
-// For the piece of code above, read the code and then answer the following questions
-
-// a) How many variable declarations are there in this program?
-
-// b) How many function calls are there?
-
-// c) Using documentation, explain what the expression movieLength % 60 represents
-// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
-
-// d) Interpret line 4, what does the expression assigned to totalMinutes mean?
-
-// e) What do you think the variable result represents? Can you think of a better name for this variable?
-
-// f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+const movieLength = 8784; // length of movie in seconds
+
+const remainingSeconds = movieLength % 60;
+const totalMinutes = (movieLength - remainingSeconds) / 60;
+
+const remainingMinutes = totalMinutes % 60;
+const totalHours = (totalMinutes - remainingMinutes) / 60;
+
+const result = `${totalHours}:${remainingMinutes}:${remainingSeconds}`;
+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?
+     //answer: we have 6 variable declarations
+
+// b) How many function calls are there?
+     //answer: there is 1 function call: 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
+    //answer:% is a remainder operator, it calculates left over seconds when movie length is divided into full minutes
+
+// d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+//answer:it subtracts the left over seconds from the total movie length to get a multiple of 60, then divides by 60 to convert that duration into whole minutes.
+
+// e) What do you think the variable result represents? Can you think of a better name for this variable?
+   //answer: formattedMovieLength, it represents the movieLength format as a time string
+
+// f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+   //answer: yes it can work but only for positive numbers representing total seconds, if the movieLength is negative it will give off an output of an invalid time value

Sprint-2/3-mandatory-interpret/3-to-pounds.js

@@ -1,27 +1,37 @@
-const penceString = "399p";
-
-const penceStringWithoutTrailingP = penceString.substring(
-  0,
-  penceString.length - 1
-);
-
-const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
-const pounds = paddedPenceNumberString.substring(
-  0,
-  paddedPenceNumberString.length - 2
-);
-
-const pence = paddedPenceNumberString
-  .substring(paddedPenceNumberString.length - 2)
-  .padEnd(2, "0");
-
-console.log(`£${pounds}.${pence}`);
-
-// This program takes a string representing a price in pence
-// The program then builds up a string representing the price in pounds
-
-// You need to do a step-by-step breakdown of each line in this program
-// 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"
+const penceString = "399p";
+
+const penceStringWithoutTrailingP = penceString.substring(
+  0,
+  penceString.length - 1
+);
+
+const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+const pounds = paddedPenceNumberString.substring(
+  0,
+  paddedPenceNumberString.length - 2
+);
+
+const pence = paddedPenceNumberString
+  .substring(paddedPenceNumberString.length - 2)
+  .padEnd(2, "0");
+
+console.log(`£${pounds}.${pence}`);
+
+// This program takes a string representing a price in pence
+// The program then builds up a string representing the price in pounds
+
+// You need to do a step-by-step breakdown of each line in this program
+// Try and describe the purpose / rationale behind each step
+
+// To begin, we can start with
+// 1. const penceString = "399p": initializes a string variable with the value "399p" representing the price in pence including the trailing letter 'p'
+
+// 2. const penceStringWithoutTrailingP = penceString.substring(0, penceString.length - 1): Extract the numeric portion of the penceString by taking characters from index 0 up to the last character removing the 'p'because 399p is not a valid number for math.
+
+// 3. const paddedPenceNumberString = penceStringWithoutTrailingP . padStart(3, "0"): it ensures the penceString is at least 3 digits long by adding leading zeros if necessary ensuring there will always be 2 digits for pence and 1 for pound.
+
+// 4. const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2): Extracts the pounds portion of the price by taking all digits except the last 2
+
+// 5. const pence = paddedPenceNumberString.substring(paddedPenceNumberString.length - 2) padEnd(2, "0") it extracts the last 2 digits representing pence ensuring it is padded to 2 digits
+
+// 6. line 18 = formats and prints the final price string with the pound symbol, amount, period and pence amount i.e "£3.99"