London | 26-ITP-January | Miriam Jorna | Sprint 1 | Coursework

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

@@ -4,3 +4,9 @@ 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 the count variable. The = operator is an assignment operator, 
+// which assigns the value on the right (count + 1) to the variable on the left (count). In this case, 
+// it takes the current value of count (which is 0), adds 1 to it, and then assigns the result (1) 
+// back to count. So after this line executes, count will have a new value of 1.
+// It has incremented with 1.              

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

@@ -5,7 +5,15 @@ 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 letter1 = firstName.charAt(0);
+let letter2 = middleName.charAt(0);
+let letter3 = lastName.charAt(0);
+
+let initials = letter1 + letter2 + letter3;
+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 +17,10 @@ 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);
+console.log(`The dir part of ${filePath} is ${dir}`);
+
+const ext = filePath.slice(lastSlashIndex + 1).split('.').pop();
+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

@@ -7,3 +7,11 @@ 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
+
+
+//We start with 2 constant (unchangeable) values
+//We use them to generate a random number between 1 and 100 with Math.random()
+//The random number will always be an integer because Math.floor() is used to round
+//down the result.
+//At the end the value "minimum" is added to guarantee that the generated "num" is at least 1
+//"num" is a random number generator with results between 1 and 100, including 1 but excluding 100 

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

@@ -1,2 +1,8 @@
-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?
+
+
+//Starting a line with two forward slashes creates a comment.
+//This makes the computer ignore the rest of that line; it will not attempt to execute it.
+//It is advisable to use this feature lots because explaining the intention of the code
+//is helpful when cooperating with other people (and for your future self) 

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

@@ -2,3 +2,8 @@
 
 const age = 33;
 age = age + 1;
+
+// The reassignment will not work because the variable is a "const" = a constant, 
+// which means it cannot be changed.
+// If a value will need to be changed later it must be declared with "let"
+// instead of "const".

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

@@ -3,3 +3,9 @@
 
 console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+
+
+// These two lines are in the wrong order. 
+// The request is to print information that has not yet been received. 
+// In order for this to work both the declaration of the variable and its value
+// need to be declared before the console.log line

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

@@ -7,3 +7,14 @@ const last4Digits = cardNumber.slice(-4);
 // 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 card number is not declared as a fixed unit = a string, it is just a set of numbers. 
+// Also, the slice method is only suitable for strings.
+
+// First the card number needs to become a string, Then it can be sliced. 
+
+const last4Digits = String(cardNumber).slice(-4);
+console.log(`The last 4 digits of the card number are ${last4Digits}`);
+
+

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

@@ -1,2 +1,7 @@
 const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+const 24hourClockTime = "08:53";
+
+// A variable name cannot start with a number. It should rather be e.g. twelveHourClockTime.
+// There's a mistake in the assignment of the clock times: the 12h clock has a 24h time
+// I'm not sure how well it works for these times to be declared as unchangeable "const"?
+// Not wrong wrong but bad practice is that the second variable has a lowercase h for Hour

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

@@ -13,10 +13,35 @@ console.log(`The percentage change is ${percentageChange}`);
 
 // a) How many function calls are there in this file? Write down all the lines where a function call is made
 
+//There are 4 function calls in this file: 
+
+carPrice = Number(carPrice.replaceAll(",", ""));
+priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ""));
+Number; //called twice
+const priceDifference = carPrice - priceAfterOneYear;
+const percentageChange = (priceDifference / carPrice) * 100;
+
+
 // 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?
 
+// There is a comma missing between te arguments in: replaceAll("," ""));  
+// It should be: replaceAll(",", "")); 
+
+
 // c) Identify all the lines that are variable reassignment statements
 
+carPrice = Number(carPrice.replaceAll(",", ""));
+priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ""));
+
+
 // d) Identify all the lines that are variable declarations
 
+const priceDifference = carPrice - priceAfterOneYear;
+const percentageChange = (priceDifference / carPrice) * 100;
+
+
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+
+// The purpose is to remove the comma from all amounts, so that they have the correct format to be seen as numbers 
+// instead of as strings. Then Number is used to do this conversion from string to number.
+

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

@@ -13,13 +13,43 @@ console.log(result);
 
 // a) How many variable declarations are there in this program?
 
+// There are 6: movieLength, remainingSeconds, totalMinutes, remainingMinutes, totalHours, 
+// and result
+
+
 // b) How many function calls are there?
 
+// There is 1: console.log 
+
+
 // c) Using documentation, explain what the expression movieLength % 60 represents
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
 
+// The expression movieLength % 60 calculates the remainder when movieLength is divided by 60.
+// For instance if the movieLength were 121, the remainder of this division would be 1.
+
+
+
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
 
+const totalMinutes = (movieLength - remainingSeconds) / 60;
+
+// This line calculates the length of the movie in whole minutes 
+
+
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
 
+// "result" represents the result of the calculations, being the total length of the movie 
+// transcribed to hours/minutes/seconds. It would have been much clearer to not give the mathematical 
+// output as the name but instead the usability of this output, such as "movieLengthHMS" or the clearer 
+// but rather lengthy movieLengthHoursMinutesSeconds
+
+
+
+
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+
+// Yes, as long as they are positive numbers. They should also be integers. 
+// I have tried to give half-seconds and this did not break the code, but the half-second was 
+// ignored in the output
+

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

@@ -13,7 +13,6 @@ const pounds = paddedPenceNumberString.substring(
 
 const pence = paddedPenceNumberString
   .substring(paddedPenceNumberString.length - 2)
-  .padEnd(2, "0");
 
 console.log(`£${pounds}.${pence}`);
 
@@ -25,3 +24,17 @@ console.log(`£${pounds}.${pence}`);
 
 // To begin, we can start with
 // 1. const penceString = "399p": initialises a string variable with the value "399p"
+
+// 2. The next step in lines 3-6 strips the letter p from the amount. 
+// Without the p the amount-string becomes a number: 399
+
+// 3. In lines 8-12 the number is padded with leading zeros if needed to ensure it has at 
+// least three digits. This is needed for the last step: the conversion into an amount in 
+// pounds, where the format requires at least three digits
+
+// 4. In lines 14-17 the number is split into pounds and pence. 
+// In line 16 the number is padded with trailing zeros to ensure the pence always have two digits
+
+// 5. Then in line 20 the pounds and pence are put in a string with the pound sign in front of 
+// it, and printed to the console
+