London | 26-ITP-Jan | Boualem Larbi Djebbour | sprint 1 | Coursework

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

@@ -3,4 +3,4 @@ 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
+// the third line used the the assignment operator '=' to reassign the variable count to the initial value which is zero incremented by one  resulting to the value 1

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

@@ -5,7 +5,11 @@ 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);
+// or
+let initials = firstName[0] + middleName[0] + lastName[0];
+// or but rarely used and not recommended because it might cause bugs
+let initials = firstName[0].concat(middleName[0], lastName[0]);
 
 // 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+1);
+const ext = filePath.slice(-3); //the extention of the file is always the last three characters in the path
+//or
+const lastPointIndex = filePath.lastIndexOf(".");
+const ext = filePath.slice(lastPointIndex+1);
 
-// https://www.google.com/search?q=slice+mdn
+// https://www.google.com/search?q=slice+mdn

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

@@ -7,3 +7,14 @@ const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
 // 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
+
+// the num represents a value with limited interval and that's why
+// the num assigned to a value that's in the dor of an expression
+// the math object is invoked to perform some mathematical tasks
+// the random method is invoked to get a random number between 0 and 1
+// the random number is multiplied by 100 
+// the floor method is invoked to round down the result to its nearest integer
+//  added one to the new result
+// the final result of the whole expression is what the variable num assigned to
+/* after applying the program several times, I got the idea that the program is generating 
+a value to the num variable thats always between minimum an maximum*/  

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?
+// to make the computer not running these two line we use inline comments by adding two slashes at the beginning of each line

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

@@ -1,4 +1,4 @@
 // trying to create an age variable and then reassign the value by 1
 
-const age = 33;
+let age = 33; // we should use the keyword 'let' to declare the variable 'age' to allow reassignment later 
 age = age + 1;

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

@@ -1,5 +1,7 @@
 // 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 that the variable 'cityOfBirth' is declared after the statement it is used in

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);
 
 // 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
+
+/* my prediction about why the code isn't working is because either the new variable is declared with const keyword
+or the value of the variable cardNumber is a number not a string whereas the method .slice works only with strings */
+// the error it gives 'cardNumber.slice is not a function'
+// It gives this error because the computer assumes the coder is trying to invoke a function
+// yes it is my second prediction
+// updating the expression last4Digits is assigned to, in order to get the correct value is as follows
+// method one: puting the value of the variable cardNumber into quotes
+// method two: invoking the method .toString() to convert the type of the variable from number to string

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

@@ -1,2 +1,6 @@
-const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+const _12HourClockTime = "20:53"; // identifier can not begin with a number
+// or
+const $12HourClockTime = "20:53"; // or any change that makes the identifier not stating with digit
+const _24hourClockTime = "08:53"; // identifier can not begin with a number
+// or
+const $24hourClockTime = "08:53"; // or any change that makes the identifier not stating with digit

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 +12,24 @@ 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 five function calls in this file, the lines where a call function is made are as follows:
+// line 4, replaceAll()
+// line 4, Number()
+// line 5, replaceAll()
+// line 5, Number()
+// line 10, 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 coming from line 5
+// it is a syntax error, the expression priceAfterOneYear.replaceAll("," "") ismissing a comma
+// to fix this problem we add comma between the two arguments
 
 // c) Identify all the lines that are variable reassignment statements
+// the lines that are variable reassignment statements: -line 4 -line 5
 
 // d) Identify all the lines that are variable declarations
+// the lines that are variable declarations: -line 1 -line 2 -line 7 -line 8
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+// the expression calls the replace method to replace the comma with empty string
+// converting the new string to a number to be able to perform math operations

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

@@ -12,14 +12,21 @@ 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 declaration
 
 // b) How many function calls are there?
+// there is one function call (console.log())
 
 // c) Using documentation, explain what the expression movieLength % 60 represents
+// it represents the remaining of dividing movielength by 60
 // 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?
+// it means the integer quotient of dividing movieLength by 60
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+// it represents the length of the movie in hours, minutes and seconds format
+// a better name would be: movieTimeVolume
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+// no it will not work for negative input values as it gives negative results

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

@@ -25,3 +25,8 @@ console.log(`£${pounds}.${pence}`);
 
 // To begin, we can start with
 // 1. const penceString = "399p": initialises a string variable with the value "399p"
+// line 3: calling substring method to remove the 'p' letter and keep only digits in the string
+// line 8: using padstart method to make the minimum length of the string to 3 characters by adding one zero or two to the left.
+// line 9: using substring method to take only the integer part
+// line 14: using substring method to take only the decimal part and padend method to make the minimum length of pence to 2 characters by adding zero to the right
+// line 18: calling console function to print the integer part that represents the pound and the decimal part that represents the pence seprated by point

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

@@ -16,5 +16,3 @@ function square(3) {
 // Finally, correct the code to fix the problem
 
 // =============> write your new code here
-
-

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

@@ -1,14 +1,26 @@
 // Predict and explain first...
 
-// =============> write your prediction here
+// =============> the function when called will throw an error
 
 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
+// =============> the function multiply has no return statement
 
 // Finally, correct the code to fix the problem
-//  =============> write your new code here
+//  =============> 
+function multiply(a, b) {
+  return (a * b); // we change the console.log statement with the return statement
+}
+
+console.log(`The result of multiplying 10 and 32 is ${multiply(10, 32)}`);
+
+// an extra notice: the purpose of creating a function is to reuse it when needed 
+// I've noticed that the parameters are already assigned to values 10 and 32, so I changed the code to the following:
+function multiply(a, b) {
+  return console.log(`The result of multiplying ` + a +` and ` + b +` is ` + (a * b));
+}
+multiply(10, 32);

Sprint-2/4-mandatory-interpret/time-format.js

@@ -17,7 +17,7 @@ function formatTimeDisplay(seconds) {
 // Questions
 
 // a) When formatTimeDisplay is called how many times will pad be called?
-// =============> write your answer here
+
 
 // Call formatTimeDisplay with an input of 61, now answer the following: