London | 26-ITP-May | Dagim Daniel | Sprint 1 | 1-key-exercise -count

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

@@ -4,3 +4,13 @@ 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 is updating the value of the variable `count`. 
+The `=` operator is an assignment operator, 
+which means it takes the value on the right side 
+(in this case, `count + 1`) 
+and assigns it to the variable on the left side (`count`). 
+So, it takes the current value of `count`, adds 1 to it, 
+and then stores that new value back into `count`. 
+in general, Line 3 is incrementing the value of `count` by 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]}`;
+console.log(initials);
 // https://www.google.com/search?q=get+first+character+of+string+mdn
 

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(0,lastSlashIndex);
+const ext = base.slice(base.lastIndexOf("."));
+console.log (`The directory is : ${dir}
+The extension is : ${ext}`);
 // https://www.google.com/search?q=slice+mdn

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

@@ -4,6 +4,15 @@ 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?
+        //   num represents a random integer between 1 and 100.
 // 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
+    // breaking down the expression into smaller parts.
+/* Math.floor(): this will return the largest integer less than or equal to a given number. In this case, it will round down the result of the expression inside the parentheses.
+Math.random(): this will return a random floating-point number between 0 (inclusive) and 1 (exclusive). In this case, it will generate a random number between 0 and 1 but never exactly 1.
+(maximum - minimum + 1): this will calculate the range of numbers we want to generate. In this case, it will calculate the difference between the maximum and minimum values (100 - 1 = 99) 
+and add 1 to include both endpoints (99 + 1 = 100).
+finally, the code adds the minimum value (which is 1) to the result.
+*/
+

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

@@ -1,4 +1,5 @@
 // trying to create an age variable and then reassign the value by 1
 
-const age = 33;
+let age = 33;
 age = age + 1;
+console.log(age);

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

@@ -1,5 +1,8 @@
 // Currently trying to print the string "I was born in Bolton" but it isn't working...
 // what's the error ?
 
+        //The error was ReferenceError: cannot access `cityOfBirth` before initialization    
+        //by swapping the order of the two lines, the error will be fixed.
+
 console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";

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

@@ -1,9 +1,16 @@
 const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
-
+const last4Digits = 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
+// i predict that the code doesn't work its because of two things, first i thought its case sensitive things
+// the second one is the type of variable, i thought the slice method is only for string type variable.
+
 // 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?
+/*
+    I run the code and it gives me an error that says "TypeError: cardNumber.slice is not a function".
+    so i checked the type of cardNumber using typeof operator and it returns number.
+    */
 // Then try updating the expression last4Digits is assigned to, in order to get the correct value

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

@@ -1,2 +1,6 @@
 const 12HourClockTime = "8:53pm";
 const 24hourClockTime = "20:53";
+
+    // I believe this question is about what the error might be.
+    // the error is syntaxError: and its because the variable name stats wit a number which is not allowed in Javascript.
+    // removing the number or use the number next to the string/s.

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 +12,27 @@ 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 5 function calls in this file. including methods used , 2 methods  = replaceAll(), methods are called under their object, replaceAll() is called under the string object.
+// The lines where a function call is made are:
+// Line 4: carPrice.replaceAll(",", "")
+// Line 5: priceAfterOneYear.replaceAll(",", "")
+// Line 7: 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?
+//syntaxError: missing ) after argument list, -
+//the error is occurring because of a missing "," between arguments in the replaceAll() method. in line 5.
 
 // c) Identify all the lines that are variable reassignment statements
+// The lines that are variable reassignment statements are:
+// Line 4: carPrice = Number(carPrice.replaceAll(",", ""));
+// Line 5: priceAfterOneYear = Number(priceAfterOneYear.replaceAll("," ""));
 
 // d) Identify all the lines that are variable declarations
+// The lines that are variable declarations are:
+// Line 1: let carPrice = "10,000";
+// Line 2: let priceAfterOneYear = "8,543";
+// Line 7: const priceDifference = carPrice - priceAfterOneYear;
+// Line 8: const percentageChange = (priceDifference / carPrice) * 100;
 
 // e) Describe what the expression Number(carPrice.replaceAll(",","")) is doing - what is the purpose of this expression?
+// The expression Number(carPrice.replaceAll(",","")) is converting the string value of carPrice into a number by removing the comma from the string.

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

@@ -12,14 +12,23 @@ 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?
+    // there are 6 variable declarations in this program. 
 
 // b) How many function calls are there?
+    // there is 1 function call in this program, which is the console.log().
 
 // c) Using documentation, explain what the expression movieLength % 60 represents
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Arithmetic_Operators
+    // The expression movieLength % 60 represents the remainder of the division of movieLength by 60. 
+    // In this case, it calculates the number of seconds remaining after converting the total movie length from seconds to minutes.
+    //  The modulo operator (%) returns the remainder of a division operation, so it helps to determine how many seconds are left after accounting for full minutes in the movie length.
+    // this means 8784 seconds is exactly 146 minutes and 24 seconds.
 
 // d) Interpret line 4, what does the expression assigned to totalMinutes mean?
+    // The expression assigned to totalMinutes will return the total number of minutes only leaving the seconds out.
 
 // e) What do you think the variable result represents? Can you think of a better name for this variable?
+    // the variable holds the hour,minutes and seconds a movie is long, so i prefer to name it movieDuration.
 
 // f) Try experimenting with different values of movieLength. Will this code work for all values of movieLength? Explain your answer
+    // yes, this code will work for all values of movieLength because every attributes of the movieLength variable is being calculated and converted to hours, minutes and seconds.

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

@@ -3,17 +3,17 @@ const penceString = "399p";
 const penceStringWithoutTrailingP = penceString.substring(
   0,
   penceString.length - 1
-);
+);  // remove the trailing "p" from the string
 
-const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0"); // pad the string with leading zeros to ensure it has at least 3 characters
 const pounds = paddedPenceNumberString.substring(
   0,
   paddedPenceNumberString.length - 2
-);
+); // get the substring representing the pounds by taking all characters except the last two
 
 const pence = paddedPenceNumberString
   .substring(paddedPenceNumberString.length - 2)
-  .padEnd(2, "0");
+  .padEnd(2, "0"); // get the substring representing the pence by taking the last two characters and padding it with a "0" if necessary
 
 console.log(`£${pounds}.${pence}`);
 
@@ -25,3 +25,8 @@ 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): removes the trailing "p" from the string to get the numeric part of the price in pence
+  //3. const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0"): pads the string with leading zeros to ensure it has at least 3 characters, which is useful for prices less than £1
+  //4. const pounds = paddedPenceNumberString.substring(0, paddedPenceNumberString.length - 2): extracts the substring representing the pounds by taking all characters/values except the last two
+  //5. const pence = paddedPenceNumberString.substring(paddedPenceNumberString.length - 2).padEnd(2, "0"): extracts the substring representing the pence by taking the last two characters and padding it with a "0" if necessary
+  //6. console.log(`£${pounds}.${pence}`): outputs the final formatted price in pounds and pence to the console