Sheffield | ITP September| Xiayidan Abuduxukuer | Sprint 1 | Coursework

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

@@ -4,3 +4,7 @@ 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
+
+Answer:
+
+//Line 3 is assignment statement,its taking the current value to count,then make the count to a new value.

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

@@ -5,7 +5,8 @@ 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 = ``;
+Answer:
+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

@@ -16,8 +16,10 @@ 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 = ;
+Anwer:
+const dir = filePath.slice(0, lastSlashIndex);
+const ext = base.slice(lastDotIndex + 1);
+console.log(`The dir part of ${filePath} is ${dir}`);
+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 +7,16 @@ 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
+
+Answer:
+
+//num is a random number between 1 and 100.
+
+//Math.random() makes a number between 0 and 1.
+
+//times (maximum - minimum + 1) makes it bigger.
+
+//Math.floor cuts off the decimal.
+
+//+ minimum makes sure the random number starts at 1 instead of 0
+

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

@@ -1,2 +1,6 @@
 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?
+
+Answer:
+//We can turn those lines into comments by putting // at the start.
+//Then computer ignores them but humans can still read/see them.

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

@@ -2,3 +2,10 @@
 
 const age = 33;
 age = age + 1;
+
+Answer:
+
+//This gives an error because we used const, which can't be changed.
+// If we want to update the value, we should use let instead of const.
+let age = 33;
+age = age + 1;

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

@@ -3,3 +3,12 @@
 
 console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+
+
+Answer:
+
+//Error because cityOfBirth is used before it is declared.
+//We need to define the variable first, then use it.
+
+const cityOfBirth = "Bolton";
+console.log(`I was born in ${cityOfBirth}`);

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

@@ -7,3 +7,12 @@ 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
+
+Answer:
+
+//I guessed it breaks because slice is for strings but cardNumber is a number.
+//When I try it, the error says slice is not a function (so I was right).
+//Fix: change the number to string first, then slice works.
+const cardNumber = 4533787178994213;
+const last4Digits = cardNumber.toString().slice(-4);
+console.log(last4Digits); // 4213

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

@@ -1,2 +1,10 @@
 const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+const 24hourClockTime = "08:53";
+
+
+Answer:
+
+// The first line is wrong cuz variable names can't start with a number.
+// We should rename it like hour12ClockTime or something that doesn't start with a digit.
+const hour12ClockTime = "20:53";
+const hour24ClockTime = "08:53";

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

@@ -12,11 +12,26 @@ 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
+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?
+priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ""));
+fix;
+priceAfterOneYear = Number(priceAfterOneYear.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
+let carPrice = "10,000";
+let priceAfterOneYear = "8,543";
+
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+replaceAll gets rid of the commas → "10,000" becomes "10000".
+Number() turns that string into the number 10000.
+so we can do maths with it.

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?
+6: movieLength, remainingSeconds, totalMinutes, remainingMinutes, totalHours, result.
 
 // b) How many function calls are there?
+Only 1 ; console.log(result);
 
 // c) Using documentation, explain what the expression movieLength % 60 represents
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
+% gives the leftover after dividing, so movieLength % 60 = extra seconds
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+(movieLength - remainingSeconds)/60 → takes away seconds, then gets whole minutes
+
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+It’s the time of the movie written as hours:minutes:seconds. A better name could be movieTime or formattedTime.
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+works for normal numbers, but long movies or single-digit mins/secs look weird

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

@@ -1,21 +1,30 @@
 const penceString = "399p";
+sets the price string with "p" at the end
+
 
 const penceStringWithoutTrailingP = penceString.substring(
   0,
   penceString.length - 1
 );
+//removes the p from the end
+
 
 const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
 const pounds = paddedPenceNumberString.substring(
   0,
   paddedPenceNumberString.length - 2
 );
+// makes sure it has at least 3 digits, adds 0 at start if needed
+
 
 const pence = paddedPenceNumberString
   .substring(paddedPenceNumberString.length - 2)
   .padEnd(2, "0");
+  // takes last 2 digits → pence, adds 0 at end if needed
 
 console.log(`£${pounds}.${pence}`);
+// prints the price in pounds like £3.99
+
 
 // This program takes a string representing a price in pence
 // The program then builds up a string representing the price in pounds

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

@@ -11,8 +11,12 @@ In the Chrome console,
 invoke the function `alert` with an input string of `"Hello world!"`;
 
 What effect does calling the `alert` function have?
+*It shows a popup message on the screen.*
 
 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?
+*pops up a box asking you to type something*
+
 What is the return value of `prompt`?
+*whatever the user typed (as a string)*

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

@@ -7,10 +7,14 @@ Open the Chrome devtools Console, type in `console.log` and then hit enter
 What output do you get?
 
 Now enter just `console` in the Console, what output do you get back?
+*shows a big list of all the stuff it can do, like log, assert, and other functions*
 
 Try also entering `typeof console`
 
 Answer the following questions:
 
 What does `console` store?
+*console stores all the console functions you can use.*
+
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+*the . means “use a function from console.*