London | 26-ITP-Jan | Divine Mankrado | Sprint 1 | Sprint-1

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 creates assigns the count variable, using the = assignment operator, to the 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[0] + middleName[0] + lastName[0];
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn
 

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

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

@@ -3,7 +3,10 @@ const maximum = 100;
 
 const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
 
-// In this exercise, you will need to work out what num represents?
+// 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
+// Answer: num choose a random number between 0 and 100 and adds 1 to it so that the number is between 1 and 100 instead of 0 and 99
+
 // Try logging the value of num and running the program several times to build an idea of what the program is doing
+console.log(num);

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?
+// Answer: Comment it out.

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

@@ -1,4 +1,6 @@
 // trying to create an age variable and then reassign the value by 1
 
-const age = 33;
+let age = 33;
 age = age + 1;
+
+// Answer: Syntax error, using const instead of let causes error because const variables can't be reasigned.

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}`);
+
+// Answer: Defined variable before using it.

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

@@ -1,9 +1,12 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+const last4Digits = cardNumber.toString().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
+
+// Prediction: Slice only works on strings and cardNUmber is a number.
+// Erorr message: Type error: cardNumber.slice is not a function

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

@@ -1,2 +1,4 @@
-const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+const twelveHour = "20:53";
+const twentyFourHour = "08:53";
+
+// Variable names cannot start with a number.

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
+// There are 4 function calls on lines 4 to 5.
 
 // 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?
+// Error occurs on line 5 because the second argument to replaceAll is missing quotes.
 
 // c) Identify all the lines that are variable reassignment statements
+// Line 4: carPrice = Number(carPrice.replaceAll(",", ""));
+// Line 5: priceAfterOneYear = Number(priceAfterOneYear.replaceAll(",", ""));
 
 // d) Identify all the lines that are variable declarations
+// Line 1 and line 2.
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+// The expression removes commas from the string carPrice and converts it to a number.

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

@@ -12,14 +12,20 @@ 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
 
 // 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 movieLength by 60 and returns the remainder. This gets the remaining seconds after converting movie length to minutes
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+// It converts remaining movie length from minutes into hours.
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+// The variable result represents the formatted time in hours, minutes, and seconds. A better name is formattedTime.
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+//  Yes, it will work for all cases except for negative values - the calculation would not make sense.

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

@@ -25,3 +25,18 @@ console.log(`£${pounds}.${pence}`);
 
 // To begin, we can start with
 // 1. const penceString = "399p": initialises a string variable with the value "399p"
+
+// 2. const penceStringWithoutTrailingP = penceString.substring(  0, penceString.length - 1);
+// This creates a constant variable penceStringWithoutTrailingP and splices the last character "p" from the string. Only the number remains.
+
+// 3. const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+// This creates a constant variable padedPenceNumberString and puts 0s at the start of the string until the total lenght of the string is 3.
+
+// 4. const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2);
+// This creates a variable pounds and removes two chars from the string, leaving only the pounds value.
+
+// 5. const pence = paddedPenceNumberString.substring(paddedPenceNumberString.length - 2).padEnd(2, "0");
+// This creates a variable pence and removes all chars except the last two, leaving only the pence value. It adds 0s at the end of the string until length = 2.
+
+// 6. console.log(`£${pounds}.${pence}`);
+// This prints the number of pounds and pence, this is £3.99