Manchester | 25-ITP-May | Mahtem T. Mengstu| Sprint 1 | Coursework/Sprint 1

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

@@ -1,6 +1,55 @@
-let count = 0;
+//let count = 0;
 
-count = count + 1;
+//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  returns the incremented value of count. The operator = assigns count +1 to the varibale count in the
+// left.   
+
+// Described what line three is doing.
+
+// Example from codewar (from programming workshop)
+
+function drawStairs(n) {
+	let result = "";
+	if (n < 1) return result; // nothing to do
+
+	let iCount = 0;
+	while (iCount < n) {
+		// add spaces before the I (for all lines after the first)
+		let spaceCount = 0;
+		while (spaceCount < iCount) {
+			result = result.concat(" ");
+			spaceCount = spaceCount + 1;
+		}
+
+		// add the "I"
+		result = result.concat("I");
+
+		// add a newline after each line except the last one
+		if (iCount < n - 1) {
+			result = result.concat("\n");
+		}
+
+		// update the count
+		iCount = iCount + 1;
+	}
+
+	return result;
+}
+
+console.log(drawStairs(10));
+
+/// Another example
+
+function drawStairs(n) {
+  let result = [];
+
+  for (let i = 0; i < n; i++) {
+    result[i] = `${' '.repeat(i)}I`;
+  }
+
+  return result.join('\n');
+}
+console.log(drawStairs(5));

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

@@ -5,7 +5,17 @@ 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];
+
+let initials = `${firstName[0]}${middleName[0]}${lastName[0]}`;
+
+console.log(initials)
 
 // https://www.google.com/search?q=get+first+character+of+string+mdn
 
+// Declared a variable named initials 
+
+// Used template string to display initials Line 10
+
+
+

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

@@ -17,7 +17,8 @@ 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(lastSlashIndex+1);
+const ext = base.slice(base.lastIndexOf(".") + 1);
 
+console.log(dir)
 // https://www.google.com/search?q=slice+mdn

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

@@ -7,3 +7,18 @@ 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
+
+
+// num represents the result of equation at the right hand side of the operator =
+
+// Step-1 ---> Math.random() generates a random decimal,
+// Step-2 ---> (maximum-minumum +1) is evaluated 
+// Step-3 ---> Math.random() is multiplied by (maximum-minumum +1)
+// Step-4 ---> the resukt of Step-3 is round by the method Math.floor
+// Step-5 ---> minimum is added to the result of Step-4
+
+// Thus, num represents random numbers generated between minimum 1 and maximum 100. As we run the code several times it
+// generates new numbers. 
+
+
+console.log(num);

Sprint-1/2-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?
+// 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 have solved it by adding two forward slashes (//) at the beginning of each line. 
+// The computer does not run this line too. 

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

@@ -1,4 +1,14 @@
 // trying to create an age variable and then reassign the value by 1
 
-const age = 33;
+//const age = 33;
+
+// we need to replace "const" with "let", in javascript "const" is usd for variable
+// that will nor change / will be kept constant troughout the code, where is "let"
+// lets us to reassign variable later as we have done in the lines below the variabel age
+// gets updated by one... 
+
+let age = 33;
 age = age + 1;
+
+
+console.log(age);

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

@@ -1,5 +1,9 @@
 // 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}`);
+// The variable cityOfBirth was called before it was defined, so we need to bring that variable first 
 const cityOfBirth = "Bolton";
+console.log(`I was born in ${cityOfBirth}`);
+
+// Problem has been fixed
+

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

@@ -1,9 +1,20 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+//const last4Digits = cardNumber.slice(-4);
+
+const last4Digits = cardNumber.toString().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
+
+// I think the code does not work because cardNumber variable is not stored as string.
+
+// My guess was right. 
+
+// Therefore first we need to change CardNumber variable into string before we use the slice method. 

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

@@ -1,2 +1,14 @@
 const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+const 24hourClockTime = "08:53";
+
+// Alternatively the above variable names can be corrected as follows:
+
+// Option-1
+
+const twelveHourClockTime = "20:53";
+const twentyFourHourClockTime = "08:53";
+
+// Option -2
+
+const hour12ClockTime = "20:53";
+const hour24ClockTime = "08:53";

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 +12,23 @@ 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
+
+// Ans: There are five (5) function calls, Line 4 Number() and replaceAll(), Line 5, Number() and replaceAll()
+     // Line 10 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?
 
+//  Ans: The error is coming from line 5 "("," ""));"" a comma was missing. Putting a comma solved the problem.
+
 // c) Identify all the lines that are variable reassignment statements
+
+// Ans: Line 4 carPrice and Line 5 priceAfterOneyear are variable reassignments.
 
 // d) Identify all the lines that are variable declarations
 
+//  Ans: 4 variable declaration Line 1, Line 2, Line 7 and Line 8
+
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+
+// Ans: The purpose of the expression Number(carPrice.replaceAll(",","")) is to change a string argument the contains commas passed to replaceAll()
+//   function into number, first the function replaceAll() removes the commas and then the function Number() changes it into number. 

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

@@ -1,4 +1,4 @@
-const movieLength = 8784; // length of movie in seconds
+const movieLength = -3500; // length of movie in seconds
 
 const remainingSeconds = movieLength % 60;
 const totalMinutes = (movieLength - remainingSeconds) / 60;
@@ -13,13 +13,35 @@ console.log(result);
 
 // a) How many variable declarations are there in this program?
 
+// Ans: There are 6 variable declaration: Line 1, Line 3, Line 4, Line 6, Line 7, Line 9,
+
 // b) How many function calls are there?
 
+// Ans:  There is one function call ... log()
+
 // c) Using documentation, explain what the expression movieLength % 60 represents
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
 
+// Ans: The expression movieLength % 60  returns the remainder after totalMinutes is divided by 60.
+
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
 
+// The expression is calculating how many full minutes are in the movie’s total length by removing leftover seconds(less than 60)
+
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
 
+//   Ans: the variable result represent total movie lenght, Movie duration_hr_min_sec would be better name.
+
+// In a "camel case" the following options would be better names
+// 1. MovieDurationHrMinSec 
+// 2. TotalMovieSpan
+// 3. TotalMoviePeriod
+
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+
+// Ans: I have tried with different values and it seems to work for all values, but it needs to validate to avoid entering negative values 
+// I inserted --3500 and returned 0: -58: -20  which does not mean real time representation.
+
+
+// Corrected typo reminder -----> remainder
+// Suggested better names in "camel case" a convention in Javascript

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

@@ -25,3 +25,14 @@ 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 = a string value "399" is reassigned to penceStringWithoutTrailingP after
+       // the the letter p is removed from "399p" 
+// 3. const paddedPenceNumberString = declared new variable, padStart ensures any argument passed is at least 3 digits long.
+// 4. Line 9 a new variable pence is declared and its value comes from the padded string by removing the last two strings.
+        //     eg. 399  removing 99 get 3 if the intial amount was 55 after padding it would be 055 and the pound result would be 0
+
+// 5. Line 14 const pence = declared a variable and the variable is the result after extracts the last two digits 
+      // from the pence string and pads it to 2 characters to have two digit pence string.
+
+// 6. Line 18- console.log(`£${pounds}.${pence}`); returns money amount combining pound and pence alog with the symbol £. 
+// eg. £3.99