Glasgow | Jan-26 | Elisabeth Matulian | Sprint 1 | Coursework

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
+// Line 3 reassigns the value of the variable count. For this, the assignment operator = is used. The new value of count will be an expression of count + 1.

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

@@ -5,7 +5,7 @@ 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)}`;
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn
 

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

@@ -17,7 +17,8 @@ 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("."));
+console.log(dir)
 // https://www.google.com/search?q=slice+mdn

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

@@ -7,3 +7,8 @@ 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
+
+// First, maximum - minimum + 1 is calculated, so 100 - 1 + 1 equals 100. 
+// Then, a random fractional number between 0 and 1 is chosen(except 1), for example 0.3. 
+// Next, Math.random() * 100 gives 30. 
+// Math.floor rounds this number down to the nearest integer, and the final step adds 1, giving 31.

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

@@ -1,2 +1,2 @@
-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 +1,4 @@
 // trying to create an age variable and then reassign the value by 1
 
-const age = 33;
+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";
+console.log(`I was born in ${cityOfBirth}`);

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

@@ -1,9 +1,11 @@
-const cardNumber = 4533787178994213;
+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
+// .slice() method works with String type, not with Number type. Therefore there will be an error
 // 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
+// the error is: "TypeError: cardNumber.slice is not a function" this matches my prediction. The error occurred because the method doen't work with Number type. I've changed cardNumber to a String when added quotes around the number. 

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

@@ -1,2 +1,3 @@
-const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+const ClockTime12Hour = "20:53";
+const ClockTime24Hour = "08:53";
+// variable names cannot start with a number in JavaScript syntax

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 +12,17 @@ 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) 5 functions. Lines 4,5,10
 
 // 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?
+// b) The error on the 5th line. Absence of , between arguments. 
 
 // c) Identify all the lines that are variable reassignment statements
+// c) Lines 4,5
 
 // d) Identify all the lines that are variable declarations
+// d) Lines 1,2,7,8
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+// e) This expression is removing the sign , from the carPrice variable then transforming the value from string to integer. 
+// The purpose of this expression is to convert the value of the variable into a form that is accessible for arithmetic calculations. 

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?
+// a) 6
 
 // b) How many function calls are there?
+// b) 1
 
 // c) Using documentation, explain what the expression movieLength % 60 represents
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
+// c) This expression shows the remaining part after dividing one number by another. 
+//    This way we find out how many seconds are not enough to make up a full minute.
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+// d) This way, we find out how many full minutes the film lasts. 
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+// e) This variable stores information about the exact length of the film (hours:minutes:seconds). I would call it “movieTime”
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+// f) I tried several values where the length of the film is 0 or only a few minutes/seconds, etc. The code works in all the cases I tried and returns 0 as the result if the film, for example, is less than an hour long. 

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

@@ -1,12 +1,12 @@
 const penceString = "399p";
 
-const penceStringWithoutTrailingP = penceString.substring(
+const penceStringWithoutTrailingP = penceString.substring( // 399
   0,
   penceString.length - 1
 );
 
-const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
-const pounds = paddedPenceNumberString.substring(
+const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0"); //399
+const pounds = paddedPenceNumberString.substring( //3
   0,
   paddedPenceNumberString.length - 2
 );
@@ -23,5 +23,10 @@ console.log(`£${pounds}.${pence}`);
 // 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"
+
+//3. This line truncates the string by index, excluding the last character, without the letter p. 
+//8. This line is needed in case the variable length is shorter than 3 characters. If the variable value is less than 1 pound, calling the padStart() function guarantees that there are 3 characters so that we can later convert pence to the 0.00 format (we will add the decimal point later).
+//9. saves the entire string except for the last 2 characters, i.e. the number of pounds
+//14. saves the value of the last two characters, i.e. the number of pence
+//18. this line outputs the final value in the standard format £0.00
+

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

@@ -11,8 +11,11 @@ In the Chrome console,
 invoke the function `alert` with an input string of `"Hello world!"`;
 
 What effect does calling the `alert` function have?
+Answer: A window pops up in the browser with the text “Hello world!” 
 
 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?
+Answer: A window pops up in the browser with a text input field
 What is the return value of `prompt`?
+Answer: the text that I entered in the input field that is stored in myName variable

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

@@ -5,12 +5,17 @@ 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: ƒ log() { [native code] }
 
 Now enter just `console` in the Console, what output do you get back?
+Answer: 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: Methods
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+Answer: `.` calls a method of an object.