London | 26 ITP MAY | Russom Gebremeskel | Sprint 2 | Coursework

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

@@ -4,3 +4,5 @@ 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
+
+// On line 3 is the = sign is an assignment operator and it is assigning thr count + 1 expression into the count variable.

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 = `${firstName.charAt()}${middleName.charAt()}${lastName.charAt()}`;
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn

Sprint-2/1-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);
+const ext = filePath.slice(-3);
+
+console.log(dir);
+console.log(ext);
 
 // https://www.google.com/search?q=slice+mdn

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

@@ -7,3 +7,10 @@ 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
+
+// 1. num is a variable that stores the final result of the expression assigned to it.
+// 2. The Math.random() method generates a random decimal number from 0 up but not excluding 1.
+// 3. The Math.floor() method round a decimal number down to a whole number.
+// 4. (maximum - minimum + 1) calculates how many possible whole numbers there are. 
+//    Java Script evaluates the expressions inside the inner parentheses first. 
+//    + minimum adds 1 to move the range from 0 to the minimum 1. 

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

@@ -1,2 +1,2 @@
-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-2/2-mandatory-errors/1.js

@@ -1,4 +1,4 @@
 // trying to create an age variable and then reassign the value by 1
 
-const age = 33;
+let age = 33;
 age = age + 1;

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

@@ -1,5 +1,7 @@
 // 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}`);
+
+// Java script cannot access the variable cityOfBirth before initialization.

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

@@ -1,9 +1,16 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+const last4Digits = Number(String(cardNumber).slice(-4));
+
+console.log(last4Digits);
 
 // 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() is a string method. That is why it is not working on numbers.
+// Error message: type error
+// Convert the number to string 
+// If we need to keep number we need to convert it back from string to number using Number() method

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

@@ -1,2 +1,4 @@
-const 12HourClockTime = "8:53pm";
-const 24hourClockTime = "20:53";
+const twelveHourClockTime = "8:53pm";
+const twentyFourHourClockTime = "20:53";
+
+// Variable names cannot start with a number in Java Script.

Sprint-2/3-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;
@@ -20,3 +20,16 @@ console.log(`The percentage change is ${percentageChange}`);
 // d) Identify all the lines that are variable declarations
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+
+// Answers
+
+// a) There are no function or function calls in this code.
+
+// b) The error was online 5 inside replaceAll method parentheses a comma is missing between the double quotes.
+
+// c) Line 4 carPrice. Line 5 priceAfterOneYear.
+
+// d) Line 1, 2, 7 and 8.
+
+// e) The method replaceALL is removing the comma. Then the Number method is converting the string into numbers. 
+//    The purpose is to use number operations and calculate the percentage change.

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

@@ -23,3 +23,17 @@ console.log(result);
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+
+// Answers
+
+// a) There are 6 variable declarations.
+
+// b) There are no function calls.
+
+// c) The reminder (%) operator returns the reminder left over when one operand is divided by a second operand.
+
+// d) movieLength(8784) - remainingSeconds(24) = 8760(seconds). 8760 / 60 gives us 146 minutes. totalMInutes = 146
+
+// e) result represents the length of the movie in hours, minutes, and seconds format. It can be renamed movieDuration.    
+
+// f) When displaying single digit hour, minute, or seconds it doesn't include 0 in front of the digit.

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

@@ -1,19 +1,11 @@
 const penceString = "399p";
 
-const penceStringWithoutTrailingP = penceString.substring(
-  0,
-  penceString.length - 1
-);
+const penceStringWithoutTrailingP = penceString.substring(0, penceString.length - 1);
 
 const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
-const pounds = paddedPenceNumberString.substring(
-  0,
-  paddedPenceNumberString.length - 2
-);
+const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2);
 
-const pence = paddedPenceNumberString
-  .substring(paddedPenceNumberString.length - 2)
-  .padEnd(2, "0");
+const pence = paddedPenceNumberString.substring(paddedPenceNumberString.length - 2);
 
 console.log(`£${pounds}.${pence}`);
 
@@ -25,3 +17,24 @@ console.log(`£${pounds}.${pence}`);
 
 // To begin, we can start with
 // 1. const penceString = "399p": initialises a string variable with the value "399p"
+
+// Answers
+
+// 2. const penceStringWithoutTrailingP = penceString.substring(0, penceString.length - 1):
+//    the substring() method returns the characters starting at index 0(3) up to and excluding the end(9) of penString variable. 
+//    This way only 399 is extracted of the string. Then the result is assigned to penceStringWithoutTrailingP variable.
+
+// 3. const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0"):
+//    The method padStart(3, "0") adds the string 0 before if the length of penceStringWithoutTrailingP string is less than 3 characters.
+//    It then assign it to paddedPenceNumberString variable. For example if the string is 11, it returns 011 or the string is 1, it returns 001.
+
+// 4. const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2)
+//    Again the method substring() returns the characters starting at length 0 and removing the last two characters which are the pence(00).
+//    This gives us only the pounds value and it the assigned to the pounds variable.
+
+// 5. const pence = paddedPenceNumberString.substring(paddedPenceNumberString.length - 2).padEnd(2, "0"):
+//    substring method first returns the last two characters of the paddedPenceNumberString string. 
+//    Then the padEnd() method adds a 0 if the length of the string is less than 2. Then it assigns it to pence variable.
+
+// 6. console.log(`£${pounds}.${pence}`): 
+//    Finally console.log prints the pounds and pence adding the the pound sign £ first using template literal as £3.99

Sprint-2/4-stretch-explore/chrome.md

@@ -13,3 +13,11 @@ Now try invoking the function `prompt` with a string input of `"What is your nam
 
 What effect does calling the `prompt` function have?
 What is the return value of `prompt`?
+
+Answer
+
+1. 'alert' display a message on pop up window.
+
+2. 'prompt'  asks for an input of information.
+
+3. 'prompt' return value is string.

Sprint-2/4-stretch-explore/objects.md

@@ -14,3 +14,18 @@ Answer the following questions:
 
 What does `console` store?
 What does the syntax `console.log` or `console.assert` mean? In particular, what does the `.` mean?
+
+
+Answer
+
+1. When 'console.log' entered it gave the output: 'Uncaught ReferenceError: consol is not defined'.
+
+2. When 'console' entered it gave the output: 'console {debug: ƒ, error: ƒ, info: ƒ, log: ƒ, warn: ƒ, …}'.
+
+4. 'console; stores object.
+
+5. 'console.log' print/display a value.
+
+6. 'console.assert' checks weather a condition is true or false.
+
+7. '.' means access the value inside the object.