London | 26-Sept- ITP | Hugh Mills| Sprint 2| Sprint 2 Coursework

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

@@ -4,3 +4,8 @@ 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
+
+/* 
+it is making count be the sum of count + 1.
+For example if this is part of a loop it will allow count to keep adding 1 each time the loop runs.
+*/

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

@@ -5,6 +5,6 @@ const 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.
 
-const initials = ``;
+const initials = firstName.slice(0,1) + middleName.slice(0,1) + lastName.slice(0,1);
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn

Sprint-2/1-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, filePath.lastIndexOf("/") + 1);
+const ext = filePath.slice(-4);
 
 // https://www.google.com/search?q=slice+mdn

Sprint-2/1-key-exercises/4-random.js

@@ -3,7 +3,15 @@ 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?
 // 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
+/*
+Firstly its not running as it is showing as undefined as it is lacking something like console.log
+After adding console.log(num) and running it a few times I get 62, 45, 35, 10. 
+For what it is doing: Math.floor is the sum of a random number from 0 to 0.9999... which is then multiplied by the maxium - minimun + 1, so 100 - 1 + 1.
+    That gives a number from 0-99, then then adds the minimun which is 1, so that gives a random number from 1-100.
+*/

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

@@ -1,2 +1,5 @@
 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 don't want the computer to run these 2 lines - how can we solve this problem?
+
+// giving SyntaxError 
+// You need to add // to each line or /* before the first line and */ after the last one to make it a comment.

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

@@ -2,3 +2,11 @@
 
 const age = 33;
 age = age + 1;
+
+// this gives a TypeError
+// age is already a const at the start and calling it again just as age wont work, naming it like "older" would work better:
+
+// const age = 33;
+// let older = (age + 1);
+// console.log(older)
+

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

@@ -3,3 +3,8 @@
 
 console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+
+//ReferenceError is happening as the const is after the console.log request for it, so the order is wrong.
+
+// const cityOfBirth = "Bolton";
+// console.log(`I was born in ${cityOfBirth}`);

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

@@ -1,9 +1,22 @@
-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
+
+/*
+cardNumber is giving a number and that can't be used for slice, could not remember the name for that error at this time.
+after running the code it shows thats a TypeError. cardNumber.slice is not a function
+*/
+
+const cardNumber = 4533787178994213;
+let number = cardNumber.toString()
+const last4Digits = number.slice(-4);
+console.log(last4Digits)
+
+
+

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

@@ -1,2 +1,8 @@
 const 12HourClockTime = "8:53pm";
 const 24hourClockTime = "20:53";
+
+// This is a Syntax error as cant have numbers for an identifier at the start of it. 
+// Changing to say: time12HourClock would work
+
+// const time12HourClock = "8:53pm";
+// const time24hourClock = "20:53";

Sprint-2/3-mandatory-interpret/1-percentage-change.js

@@ -12,11 +12,20 @@ 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
+    // 5 times its been called:
+    // 4 and 5 for Number and replaceAll
+    // 10 for 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?
+    // SyntaxError, its from  line 5 in replaceAll("," "")
+    // its missing a , between the two arguments so it needs to be (",", "")
 
 // c) Identify all the lines that are variable reassignment statements
+    // There are two reassignment statements in lines 4 and 5
 
 // d) Identify all the lines that are variable declarations
-
+    // They are 1,2 and 7,8 
+
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+    // It is using Number to make the string into a number but in order to do that the string needs to contain numerical letters only.
+    // So it then uses in the () to remove all of the , with nothing using the replaceAll function so that 10,000 becomes 10000

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

@@ -1,25 +1,32 @@
-const movieLength = 8784; // length of movie in seconds
+// const movieLength = 8784; // length of movie in seconds
 
-const remainingSeconds = movieLength % 60;
-const totalMinutes = (movieLength - remainingSeconds) / 60;
+// const remainingSeconds = movieLength % 60;
+// const totalMinutes = (movieLength - remainingSeconds) / 60;
 
-const remainingMinutes = totalMinutes % 60;
-const totalHours = (totalMinutes - remainingMinutes) / 60;
+// const remainingMinutes = totalMinutes % 60;
+// const totalHours = (totalMinutes - remainingMinutes) / 60;
 
-const result = `${totalHours}:${remainingMinutes}:${remainingSeconds}`;
-console.log(result);
+// const result = `${totalHours}:${remainingMinutes}:${remainingSeconds}`;
+// 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 declarations, lines 1,3,4,6,7,9
 
 // b) How many function calls are there?
+    //1 at line 10 
 
 // c) Using documentation, explain what the expression movieLength % 60 represents
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
+    //This is using a remainder, this us seeing how many times 8784 goes into 60 and what is remaining which is 24 in this case:
+    // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Remainder
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+    // It is the sum of movieLength minus remainingSeconds then divided by 60
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+    // its showing the length of the movie in hours, minutes and seconds, could be better called something like MovieDuration
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+    //Yes it will as long as the input is numerical numbers only, it does not work with any extra symbols, spaces or letters.

Sprint-2/3-mandatory-interpret/3-to-pounds.js

@@ -25,3 +25,24 @@ console.log(`£${pounds}.${pence}`);
 
 // To begin, we can start with
 // 1. const penceString = "399p": initialises a string variable with the value "399p"
+/*
+3-6. const penceStringWithoutTrailingP = penceString.substring(0, penceString.length - 1)
+  This is taking penceString and removing the p from it so its just a string with the numerical letters only.
+
+8. const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+  This is taking penceStringWithoutTrailingP ensuring that the minimum length of the numerical string is at least 3 numbers.
+  It is filling out with 0s from the front so if it was 3 it would have 003
+
+9-12. const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2);
+  this is taking paddedPenceNumberString and removing the last 2 numerical numbers from the string/
+  This takes the 399 and makes it 3
+
+
+14-16. const pence = paddedPenceNumberString.substring(paddedPenceNumberString.length - 2).padEnd(2, "0");
+  This is taking paddedPenceNumberString and first reduces the length to the last 2 numbers in the string.
+  It then uses padEnd to ensure that there is a at least two 00 if no numbers are present.
+
+18. console.log(`£${pounds}.${pence}`);
+  This shows the pounds and pence with a £ at the start and a . between them.
+  making this show the pence to pounds as £3.99
+*/