Manchester | 26-ITP-May | Abid Akhtar | Sprint 1 | Exercises

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

@@ -1,6 +1,9 @@
-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 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
+
+
+// In line 3 JS takes the current value of count which is 0, adds 1 to it and then stores the result back into count variable on the left.

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

@@ -1,11 +1,12 @@
-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 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 = `${firstName.charAt(0)} ${middleName.charAt(0)} ${lastName.charAt(0)}`;
+
+// https://www.google.com/search?q=get+first+character+of+string+mdn
+
+console.log(initials);

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

@@ -1,23 +1,24 @@
-// 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 = base.slice(base.lastIndexOf(".") + 1);
+
+
 // https://www.google.com/search?q=slice+mdn

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

@@ -1,9 +1,25 @@
-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;
+
+// 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
+
+
+/*
+
+In this exercise, num is a variable that stores the random whole number generated by the expression so it can be used later in the program.
+
+1. Math.randon() picks a random decimal number  
+
+2. maximum - minimum + 1; finds how many numbers are in the range
+
+3. Math.floor() rounds the decimal down
+
+4. +minimum adds the minimum value
+
+
+*/

Sprint-1/2-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? 
+
+ */

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

@@ -1,4 +1,5 @@
-// 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
+
+let age = 33;
+age = age + 1;
+

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";
+// 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}`);

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

@@ -1,9 +1,13 @@
-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.toString().slice(-4);
+
+console.log(last4Digits);
+
+// This code will not work as written because cardNumber is a number, and numbers do not have a .slice() method.
+
+// 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-1/2-mandatory-errors/4.js

@@ -1,2 +1,2 @@
-const 12HourClockTime = "8:53pm";
-const 24hourClockTime = "20:53";
+const _12HourClockTime = "8:53pm";
+const _24hourClockTime = "20:53";

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

@@ -1,22 +1,60 @@
-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
+
+// 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?
+
+/*
+
+a) How many function calls are there?
+
+There are 5 function calls. 
+
+1. carPrice.replaceAll(",", "")
+2. Number(......)
+3. priceAfterOneYear.replaceAll(",", "")
+4.  Number(......)
+5. console.log(.....)
+
+b) Why is the error occurring? 
+
+Because of the missing comma in the function call ReplaceAll() on line 5
+
+c) Variable reassignments
+
+1. carPrice = Number(carPrice.replaceAll(",", ""));
+2. priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", ""));
+
+d) all the variable declarations
+
+1. let carPrice = "10,000";
+2. let priceAfterOneYear = "8,543";
+3. const priceDifference = carPrice - priceAfterOneYear;
+4. const percentageChange = (priceDifference / carPrice) * 100;
+
+
+e)What is the expression doing?
+
+The replaceAll() removes commas from the string and Number() function call converts the string to a number.
+
+The expression removes the commas from the price string and converts the result into a number so it can be used in mathematical calculations.
+
+
+*/

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

@@ -1,25 +1,63 @@
-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?
+
+// 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
+
+/*  
+
+a)variables declarations
+
+1. There are 6 variable declarations 
+
+b) Function calls
+
+There is only 1 function call
+
+console.log(result);
+
+c)Using documentation, explain what the expression movieLength % 60 represents
+
+According to the JavaScript documentation, the remainder (%) operator returns the remainder left over after one number is divided by another. 
+
+So movieLength % 60  means Divide movieLength by 60 and return the remainder.
+
+d) Interpret line 4. What does the expression assigned to totalMinutes mean?
+
+It means remove the leftover seconds from the total movie length, then divide by 60 to calculate the total number of whole minutes.
+
+
+e) What do you think the variable result represents? Can you think of a better name?
+
+It stores the movie length formatted as hours:minutes:seconds
+
+A better variable name could be formattedTime
+
+
+f) Try experimenting with different values of movieLength.
+
+It works correctly for positive whole numbers (integers) representing seconds. However, there are some cases where it doesn't produce ideal results like:
+
+const movieLength = -100;
+
+*/