London | 25-ITP-SEP | Shaghayegh Shirinfar| Sprint 2 | coursework/sprint-2

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
+    //Answer : Line 3 increases the value of count by 1 and then reassigns it to count with new value.

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 +17,7 @@ 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 = base.slice(base.lastIndexOf("."));
 
 // https://www.google.com/search?q=slice+mdn

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

@@ -3,7 +3,18 @@ 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?
+
+    //Answer : num represents a random integer between 1 and 100
+
+
 // 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
+
+    //1- Math.floor(...) rounds the number down to the nearest whole number, giving an integer from 0 to 99.
+    //2- Math.random()  generates a decimal number between 0 and 1.
+    //3- Math.random() * (maximum - minimum + 1) make sure that decimal to a range from 0 up to (maximum - minimum + 1).
+
+
+

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?
+
+// Answer : we put them in comment syntax

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;
+let age = 33;
 age = age + 1;
+console.log(age);

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

@@ -1,5 +1,9 @@
 // Currently trying to print the string "I was born in Bolton" but it isn't working...
-// what's the error ?
+// what's the error ? 
+//                  const was declared after using it , we have to declare a variable first and then use it.
+
+// console.log(`I was born in ${cityOfBirth}`);
+// const cityOfBirth = "Bolton";
 
-console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+console.log(`I was born in ${cityOfBirth}`);

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

@@ -1,9 +1,14 @@
-const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+// 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);

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

@@ -1,2 +1,5 @@
-const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+ // const 12HourClockTime = "20:53"; 
+// const 24hourClockTime = "08:53";
+
+
+//identifiers cannot start with a number in Javascript.

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;
@@ -11,12 +11,17 @@ 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
+// a) How many function calls are there in this file? Write down all the lines where a function call is made : 
+    //Answer : 5 functions 
 
 // 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?
+    //Answe: line 5 . we need a comma (,) between the arguments.puting (,) between ("," "")
 
-// c) Identify all the lines that are variable reassignment statements
+// c) Identify all the lines that are variable reassignment statements :
+    //Answe: line 4 and line 5
 
 // d) Identify all the lines that are variable declarations
+    //Answer: line 1, 2, 6, 7 
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+    //Answer: Remove formatting commas from the price string and then convert it to a number so we can do arithmetic.

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

@@ -11,15 +11,27 @@ 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?
+// a) How many variable declarations are there in this program? 
+  //Answer: 6
+
 
 // b) How many function calls are there?
+   //Answer: 1
+
 
 // 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 the modulus operator and movieLength % 60 gives the remainder when movieLength is divided by 60.
+
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+   //Answer: movieLength - remainingSeconds → subtracts the leftover seconds, leaving only the total number of seconds that make full minutes
+   //Dividing by 60 converts those seconds to total whole minutes So totalMinutes is the total minutes in the movie ignoring leftover seconds
+
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+   //Answer: result is a string representing the movie length in HH:MM:SS format and better name MovieTimeFormat
+
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+   //Answer: It  just works for positive integer

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

@@ -1,21 +1,29 @@
 const penceString = "399p";
+//Initialize a string variable representing the price in pence with a trailing "p" characte
 
 const penceStringWithoutTrailingP = penceString.substring(
   0,
   penceString.length - 1
 );
+//Remove the "p" so we can manipulate the numeric value 
 
 const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+// Pad the string to at least 3 digits so Makes it easier to separate pounds and pence consistently.
+
 const pounds = paddedPenceNumberString.substring(
   0,
   paddedPenceNumberString.length - 2
 );
+//Extract the pounds part so This gives the whole pounds part of the price.
 
 const pence = paddedPenceNumberString
   .substring(paddedPenceNumberString.length - 2)
   .padEnd(2, "0");
 
+  //Extract the pence part so Ensures pence is always 2 digits.
+
 console.log(`£${pounds}.${pence}`);
+//Combine pounds and pence into a formatted string
 
 // This program takes a string representing a price in pence
 // The program then builds up a string representing the price in pounds

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

@@ -11,8 +11,12 @@ In the Chrome console,
 invoke the function `alert` with an input string of `"Hello world!"`;
 
 What effect does calling the `alert` function have?
+ answer : Displays a pop-up dialog box with a message and an OK button; execution pauses until OK is clicked.
 
 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?
+Displays a pop-up dialog box with a message and a text input field; execution pauses until OK or Cancel is clicked.
+
 What is the return value of `prompt`?
+Returns the string entered by the user if OK is clicked, or null if Cancel is clicked.

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

@@ -5,12 +5,18 @@ In this activity, we'll explore some additional concepts that you'll encounter i
 Open the Chrome devtools Console, type in `console.log` and then hit enter
 
 What output do you get?
+Answer : It shows  ƒ log() { [native code] }.
 
 Now enter just `console` in the Console, what output do you get back?
+Answer : It shows console {debug: ƒ, error: ƒ, info: ƒ, log: ƒ, warn: ƒ, …}
 
 Try also entering `typeof console`
+Answer:object
 
 Answer the following questions:
 
 What does `console` store?
+Answer:console is an object that stores methods for logging and debugging, like log, error, warn, assert, etc.
+
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+Answer: The . accesses a property or method of the console object.

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

@@ -1,5 +1,7 @@
 // Predict and explain first...
-//  =============> write your prediction here
+//  =============> Prediction:
+// Calling capitalise("hello") will cause an error:
+// "Identifier 'str' has already been declared"
 
 // call the function capitalise with a string input
 // interpret the error message and figure out why an error is occurring
@@ -9,5 +11,15 @@ function capitalise(str) {
   return str;
 }
 
-// =============> write your explanation here
-// =============> write your new code here
+// =============> Explanation:
+// The error happens because 'str' is already a parameter.
+// We cannot declare another variable with the same name inside the function.
+
+// =============> Corrected Code:
+function capitalise(str) {
+  str = `${str[0].toUpperCase()}${str.slice(1)}`;
+  return str;
+}
+
+// Example
+console.log(capitalise("hello")); // Output: "Hello"

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

@@ -1,20 +1,29 @@
 // Predict and explain first...
 
 // Why will an error occur when this program runs?
-// =============> write your prediction here
-
-// Try playing computer with the example to work out what is going on
+// =============> Prediction:
+// There will be an error because 'decimalNumber' is declared twice inside the function
+// and console.log(decimalNumber) outside the function will not work.
 
+// Original code:
 function convertToPercentage(decimalNumber) {
-  const decimalNumber = 0.5;
+  const decimalNumber = 0.5; //  cannot declare again
   const percentage = `${decimalNumber * 100}%`;
-
   return percentage;
 }
 
-console.log(decimalNumber);
+console.log(decimalNumber); //  not defined
+
+// =============> Explanation:
+// 1. The function already has a parameter called 'decimalNumber', so using 'const decimalNumber' again is not allowed.
+// 2. The variable 'decimalNumber' only exists inside the function.
+//    You cannot use it outside the function.
 
-// =============> write your explanation here
+// =============> Corrected Code:
+function convertToPercentage(decimalNumber) {
+  const percentage = decimalNumber * 100 + "%"; // calculate percentage
+  return percentage;
+}
 
-// Finally, correct the code to fix the problem
-// =============> write your new code here
+// Example
+console.log(convertToPercentage(0.5)); // Output: "50%"

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

@@ -3,18 +3,26 @@
 
 // this function should square any number but instead we're going to get an error
 
-// =============> write your prediction of the error here
+// =============> Prediction of the error:
+// The function will give an error because '3' is not a valid variable name. 
+// Function parameters must have names, not numbers.
 
 function square(3) {
     return num * num;
 }
 
-// =============> write the error message here
+// =============> Error message:
+// SyntaxError: Unexpected number
 
-// =============> explain this error message here
+// =============> Explanation of the error:
+// 1. You cannot use a number as a parameter name. 
+// 2. Also, 'num' is not defined inside the function, so it will cause another error if we fix the parameter first.
 
 // Finally, correct the code to fix the problem
 
-// =============> write your new code here
+// =============> Corrected Code:
+function square(num) {
+    return num
+}
 
 

Sprint-2/2-mandatory-debug/0.js

@@ -1,14 +1,26 @@
 // Predict and explain first...
 
-// =============> write your prediction here
+// =============> Prediction:
+// The program will print "The result of multiplying 10 and 32 is undefined"
+// because the function multiply does not return a value, it only prints to the console.
 
 function multiply(a, b) {
   console.log(a * b);
 }
 
 console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
 
-// =============> write your explanation here
+// =============> Explanation:
+// 1. The function multiply(a, b) uses console.log inside the function, but it does not return anything.
+// 2. When we use ${multiply(10, 32)} inside the string, it tries to use the return value of multiply.
+// 3. Since there is no return, JavaScript treats it as undefined.
 
-// Finally, correct the code to fix the problem
-//  =============> write your new code here
+// =============> Corrected Code:
+// We need the function to return the result instead of printing it.
+
+function multiply(a, b) {
+  return a * b;
+}
+
+console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
+// Output: "The result of multiplying 10 and 32 is 320"

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

@@ -1,5 +1,8 @@
 // Predict and explain first...
-//  =============> write your prediction here
+
+// =============> Prediction:
+// The program will print "The sum of 10 and 32 is undefined"
+// because the function returns nothing due to the 'return;' line.
 
 function sum(a, b) {
   return;
@@ -8,6 +11,17 @@ function sum(a, b) {
 
 console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
 
-// =============> write your explanation here
-// Finally, correct the code to fix the problem
-//  =============> write your new code here
+// =============> Explanation:
+// 1. In JavaScript, as soon as the function hits 'return;' it stops and returns undefined.
+// 2. The line 'a + b;' is never reached because it's after the return statement.
+// 3. Therefore, the function does not actually return the sum.
+
+// =============> Corrected Code:
+// We need to return the sum directly.
+
+function sum(a, b) {
+  return a + b;
+}
+
+console.log(`The sum of 10 and 32 is ${sum(10, 32)}`);
+// Output: "The sum of 10 and 32 is 42"