Birmingham|25-ITP-SEP|Hadi Vahidi|Sprint 1|coursework/sprint-1

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

@@ -4,3 +4,7 @@ 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 count by adding 1 to its current value, so count now equals 1 and every time we run the code it will increment by 1.

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

@@ -5,7 +5,9 @@ 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)}`;
+
+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 +17,11 @@ 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(`The dir part of ${filePath} is ${dir}`);
+
+console.log(`The ext part of ${filePath} is ${ext}`);
+
+// https://www.google.com/search?q=slice+mdn

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

@@ -5,5 +5,31 @@ 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
+
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random
+// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/floor
+// 
+
+//Mach.random() - generates a random number between 0 (inclusive) and 1 (exclusive):
+const num1=Math.random();
+console.log(num1);
+
+const num3=(maximum - minimum + 1);
+//(maximum - minimum + 1) - calculates the range of numbers we want (in this case, 100 - 1 + 1 = 100)
+//so by adding this to our random number we are scaling it to be between 0 and 100
+console.log(num3);
+const num2=Math.random()*(maximum - minimum + 1);
+console.log(num2);
+//until this point we have a random number between 0 (inclusive) and 100 (exclusive)but is can be a decimal number
+// Math.floor() - rounds down to the nearest whole number, so we now have a random integer between 0 and 99
+
+const num5 = Math.floor(Math.random() * (maximum - minimum + 1)) ;
+console.log(`it suppose to be a rounded number from 0-99  ${num5}`);
+
+//finally By adding 1, the number will be between 1 and 100, including both.
+
+console.log(`it suppose to be a rounded number from 1-100  ${num}`);
+
 // 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
+

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

@@ -1,2 +1,4 @@
-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?*/
+
+// we can use comments to ignore these lines of code, in javascript we use // for single line comments and /* */ for multi line comments

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

@@ -1,4 +1,22 @@
 // trying to create an age variable and then reassign the value by 1
 
+
+
 const age = 33;
 age = age + 1;
+console.log(age);
+/*the constant variable cannot be reassigned a new value
+so in lin 6 we will get an error because it can not reassign the age variable with a new value of age + 1 which in this case is 34 
+here is the error message we will get:/home/cyf/CYF/ITP/Module-Structuring-and-Testing-Data/Sprint-1/2-mandatory-errors/1.js:6
+age = age + 1;
+    ^
+
+TypeError: Assignment to constant variable.
+
+ to fix this error we can use let instead of const because let variable can be reassigned a new value*/
+
+let age2 = 33;
+age2 = age2 + 1;
+console.log(age2);
+
+// now it will work fine and the output will be 34 and every time we run the code it will increase by 1

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

@@ -1,5 +1,17 @@
 // 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}`);
+//console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+
+/*/home/cyf/CYF/ITP/Module-Structuring-and-Testing-Data/Sprint-1/2-mandatory-errors/2.js:4
+console.log(`I was born in ${cityOfBirth}`);
+                             ^
+
+ReferenceError: Cannot access 'cityOfBirth' before initialization
+
+this error is because we are trying to access the variable cityOfBirth before it is initialized and assigned a value.
+ the console.log should be after the variable declaration and assignment
+
+*/
+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.toString().slice(-4);
+console.log(`The last 4 digits of my card number are ${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
+
+
+
+//it doesn't work because the slice method is used for strings and arrays but cardNumber is a number so it doesn't have the slice method.
+
+
+
 // 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
+// to fix this error we can convert the number to a string using the toString() method before applying the slice method

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

@@ -1,2 +1,7 @@
-const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+const twelveHourClockTime = "08:53";
+const twentyFourHourClockTime = "20:53";
+
+//tha variable names are cannot start with a number
+// so the variable name 12HourClockTime is not valid because it starts with a number
+// to fix this error we can change the variable name to twelveHourClockTime and as is not relevant to the time format
+// so we can swap the variable names.

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

@@ -2,21 +2,63 @@ 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;
 
-console.log(`The percentage change is ${percentageChange}`);
+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 four function calls in total: two in the line
+
+carPrice = Number(carPrice.replaceAll(",", ""));
+
+and two in the line
+
+priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ""));
+
+In each line, one function is nested inside the other, so both lines contain two function calls each.*/
+
+
+
 // 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?
 
+
+/*priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ""));
+                                                        ^^^
+
+SyntaxError: missing ) after argument list
+the error is because a missing comma in the replaceAll method argument list
+*/
+
+
 // c) Identify all the lines that are variable reassignment statements
 
+
+
+/*carPrice = Number(carPrice.replaceAll(",", ""));
+ priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ""));
+ these two lines are variable reassignment statements because we are reassigning a new value to the existing variables carPrice and priceAfterOneYear.*/
+
 // 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;
+
+these four lines are variable declaration statements because we are declaring new variables:
+carPrice, priceAfterOneYear, priceDifference and percentageChange using let and const keywords.*/
+
+
+
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+
+/*first removes all commas from the string carPrice using replaceAll(",", ""), and then converts the resulting string into a number using Number().*/

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

@@ -12,14 +12,59 @@ 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 six variable declarations in this program:
+1. movieLength
+2. remainingSeconds
+3. totalMinutes
+4. remainingMinutes
+5. totalHours
+6. result
+*/
 
 // b) How many function calls are there?
 
+        /*There are no function calls in this code. Everything here is using operators and expressions, not calling functions.*/
+
 // 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 in JavaScript is the remainder operator. It divides the left-hand number by the right-hand number and returns the remainder.
+
+        So in this case:
+
+        movieLength % 60
+
+        divides movieLength (8784) by 60 and gives the remaining seconds, which is 24.*/
+
+
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
 
+        /*The expression
+
+        totalMinutes = (movieLength - remainingSeconds) / 60;
+
+        subtracts the leftover seconds from the total seconds so that we get a whole number of minutes. 
+        Then it divides by 60 to convert seconds into minutes without any decimal part.*/
+
+
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+        /*The variable result represents the length of the movie in the format hours:minutes:seconds.
+
+        A better name could be something like:
+
+        movieDurationFormatted
+
+        formattedDuration
+
+        movieLengthHMS (HMS = hours, minutes, seconds)*/
+
+// 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 non-negative values:
+
+        If the movie is less than an hour, totalHours is 0, so we get 0:MM:SS.
+
+        If the movie is less than a minute, both totalHours and remainingMinutes are 0, so we get 0:0:SS.
+
+        For larger movies, it correctly calculates hours, minutes, and seconds.
 
-// f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+        The only exception would be negative values, which aren’t realistic for a movie length.*/

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

@@ -1,27 +1,69 @@
-const penceString = "399p";
+const penceString = "3679p";
 
-const penceStringWithoutTrailingP = penceString.substring(
-  0,
-  penceString.length - 1
-);
+const penceStringWithoutTrailingP = penceString.substring(0, penceString.length - 1);
+
+console.log(penceStringWithoutTrailingP);
 
 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(paddedPenceNumberString);
+
+const pounds = paddedPenceNumberString.substring( 0, paddedPenceNumberString.length - 2);
+
+console.log(pounds);
+
+const pence = paddedPenceNumberString.substring(paddedPenceNumberString.length - 2).padEnd(2, "0");
+
+console.log(pence);
 
 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"
+
+/*1. const penceString = "399p";
+
+We create a variable called penceString and give it the value "399p".
+
+This is the price in pence, written as text.
+
+2. const penceStringWithoutTrailingP = penceString.substring(0, penceString.length - 1);
+
+We remove the last letter "p" from the string.
+
+Now we only have the numbers, for example "399".
+
+**3. const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+
+We make sure the string has at least 3 characters by adding zeros at the start if needed.
+
+Example: "50" becomes "050" and "5" becomes "005".
+
+4. const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2);
+
+We take all characters except the last two.
+
+These characters are the pounds. Example: "399" → "3" pounds.
+
+5. const pence = paddedPenceNumberString.substring(paddedPenceNumberString.length - 2).padEnd(2, "0");
+
+We take the last two characters. These are the pence.
+
+We add a zero at the end if needed to always have two digits. Example: "5" → "05".
+
+6. console.log(£${pounds}.${pence});
+
+We show the price in pounds and pence.
+
+Example: "399p" → £3.99, "50p" → £0.50. */

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

@@ -6,11 +6,21 @@ Open the Chrome devtools Console, type in `console.log` and then hit enter
 
 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`
+'object'
 
 Answer the following questions:
 
 What does `console` store?
+
+console stores different functions (like log, assert, warn, error) that you can use to interact with the console.
+
+
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+console.log("Hello") means: Look in the console object, find the log function, and run it with "Hello" as the argument.