Glasgow | 26-ITP-May | Chan Yat Long | Sprint 1 | Coursework

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

@@ -1,6 +1,10 @@
+
 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
+In line 3 , the new item adds 1 to turn count into a new value . 
+
+1 adds into an old value and update its own value ,  it becomes a new value now.

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 = ``;
+
+function first(firstName, middleName, lastName){
+
+    let initials = firstName.slice(0,1) + middleName.slice(0,1) + lastName.slice(0,1);
+
+  return `${initials}`;
+}
+console.log(first(firstName, middleName, lastName));
+
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn
 

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

@@ -11,13 +11,26 @@
 
 const filePath = "/Users/mitch/cyf/Module-JS1/week-1/interpret/file.txt";
 const lastSlashIndex = filePath.lastIndexOf("/");
+
+// 1. Get the base (file.txt)
 const base = filePath.slice(lastSlashIndex + 1);
 console.log(`The base part of ${filePath} is ${base}`);
 
-// Create a variable to store the dir part of the filePath variable
+const dir =  filePath.slice(0, lastSlashIndex);
+
+// Create a variable to store the dir part of the filePath 
+const ext =  filePath.slice(filePath.lastIndexOf(".") + 1); 
+
 // Create a variable to store the ext part of the variable
 
-const dir = ;
-const ext = ;
 
-// https://www.google.com/search?q=slice+mdn
+// 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;
 
+Math.floor is a function to make sure it is a whole number.
+
+The fuction will randomly choose a decimal number from 0 - 1. 
+After that will do the Math(100-1+1) and multiply the decimal value and add 1.
+
+
+
+
 // 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
+
+
+

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? 
+

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

@@ -1,4 +1,7 @@
 // trying to create an age variable and then reassign the value by 1
 
-const age = 33;
-age = age + 1;
+let age = 0; // Initialize the age variable
+age = age + 1; // Reassign the value by 1
+console.log(age);
+
+

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

@@ -1,5 +1,5 @@
 // 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";
+const cityOfBirth = "BOlton";
+const sentence = `I was born in ${cityOfBirth}`;
+console.log(sentence);

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

@@ -1,5 +1,13 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+const last4Digits = cardNumber.toString().slice(-4);
+console.log(last4Digits);
+
+because it doesn't have console.log, so it doesn't print the result. 
+but it gives the function errors.
+
+it is not what I expected, because we should change the number into string, because it is not a
+function.
+
 
 // The last4Digits variable should store the last 4 digits of cardNumber
 // However, the code isn't working

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

@@ -1,2 +1,6 @@
-const 12HourClockTime = "8:53pm";
-const 24hourClockTime = "20:53";
+const twelvehourClockTime = "8:53pm";
+const twentyfourhourClockTime = "20:53";
+
+console.log(twelvehourClockTime);
+console.log(twentyfourhourClockTime);
+

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 +12,37 @@ 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
+6 
+
+
+carPrice = Number(carPrice.replaceAll(",", ""));
+priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", ""));
+
+console.log(`The percentage change is ${percentageChange}`);
+
 
 // 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?
+It lacks comma insides the replaceAll.
 
-// c) Identify all the lines that are variable reassignment statements
 
+// 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
+let carPrice = "10,000";
+let priceAfterOneYear = "8,543";
+
+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?
+It is to take out the comma insides the number of carPrice.
+
+
+
+
+
+
+
+
+

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

@@ -1,25 +1,33 @@
-const movieLength = 8784; // length of movie in seconds
+const movieLength = 3540; // length of movie in seconds
 
 const remainingSeconds = movieLength % 60;
 const totalMinutes = (movieLength - remainingSeconds) / 60;
 
 const remainingMinutes = totalMinutes % 60;
 const totalHours = (totalMinutes - remainingMinutes) / 60;
 
-const result = `${totalHours}:${remainingMinutes}:${remainingSeconds}`;
-console.log(result);
+const formattedtime = `${totalHours}:${remainingMinutes}:${remainingSeconds}`;
+console.log(formattedtime);
 
 // 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?
-
+6
 // b) How many function calls are there?
-
+1
 // c) Using documentation, explain what the expression movieLength % 60 represents
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
 
+It divides totalMinutes into 60, see how much remainingMinutes left.
+
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+After deducting the totalMinutes, and divide the second. How much do he have the totalMinutes ?
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+ We can use formmattedtime to point out the time has been formatted.
+
+ // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+for one hour = 3600 second .      1:00:00. No, it does not work here, because the remaining minutes and second forgets the extra zero.
 
-// f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+//for 59 minutes =  3540 second .  0:59:0   No, it does not work here, because the remaining seconds and total hour forgets the extra zero.
+for seconds =  6 seconds .  0:0:6.  No, it does not work here, because the totalHours, remainingMinutes and remaining seconds forgets the extra zero.

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

@@ -24,4 +24,32 @@ console.log(`£${pounds}.${pence}`);
 // 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"
+1. const penceString = "399p": initialises a string variable with the value "399p"
+2.
+const penceStringWithoutTrailingP = penceString.substring(
+  0,
+  penceString.length - 1
+);  the purpose of this is to take out the p.
+
+
+3.
+const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+if it is shorter than 3 characters, the 0 will add in front of the number  ;  but 399 is already 3 numbers so we donot need to do anything.
+
+
+
+4. const pounds = paddedPenceNumberString.substring(
+  0,
+  paddedPenceNumberString.length - 2
+);  the length of the string is 3 , after -2 , it will become 1. The const pounds will take out 3 and it will become 3.
+
+
+5. const pence = paddedPenceNumberString
+  .substring(paddedPenceNumberString.length - 2)
+  .padEnd(2, "0");
+
+  It will take out the number from the end to 1 ; so it will have 99. 
+
+6.console.log(`£${pounds}.${pence}`);  
+
+Finally it will put the pounds and the pence into the template and print it out. The result will be £${3}.${99} ;