Msatd sprint1

Sprint-1/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? 
+because these sentences were not nested inside JS's comment syntax.*/

Sprint-1/errors/1.js

@@ -1,4 +1,6 @@
 // trying to create an age variable and then reassign the value by 1
-
-const age = 33;
+/*when const is used to create a variable, it can not be reassigned. So for this practice, i replace
+with let to fix this error.*/ 
+let age = 33;
 age = age + 1;
+console.log(age);

Sprint-1/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 ?
+/*the answer is related to the order that the code was written. the variable declaration followed console.log
+instead of preceding it resulting in a reference error. I cut the variable declaration and pasted it above
+console.log to resolve the problem.*/ 
 
-console.log(`I was born in ${cityOfBirth}`);
 const cityOfBirth = "Bolton";
+console.log(`I was born in ${cityOfBirth}`);
+

Sprint-1/errors/3.js

@@ -1,9 +1,12 @@
-const cardNumber = 4533787178994213;
-const last4Digits = cardNumber.slice(-4);
+const cardNumber = 4533787178994213; // const cardNumber = `${4533787178994213}` also fixes the error by changing data type to string.
+const last4Digits = cardNumber.toString().slice(-4);
+console.log(`The last 4 digits of the card number are: ${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?
+/* the answer: slice() method does only work on strings and arrays. it does not work on numbers.
+so I fixed it by changing the expression in Last4Digits variable.  */
 // Then try updating the expression last4Digits is assigned to, in order to get the correct value

Sprint-1/errors/4.js

@@ -1,2 +1,5 @@
-const 12HourClockTime = "20:53";
-const 24hourClockTime = "08:53";
+let HourClockTime = "20:53";
+hourClockTime = "08:53"; 
+console.log(hourClockTime); // Output: 08:53
+/*Javascript variables can not be started with numbers. I changed const to let so that the variable can 
+be reassigned to a new value. */

Sprint-1/exercises/count.js

@@ -1,6 +1,8 @@
 let count = 0;
 
 count = count + 1;
+/*line 3 reassigns the value that was passed onto count variable by using an arithmetic operator to add 
+1 to count variable's value.*/
 
 // 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

Sprint-1/exercises/decimal.js

@@ -1,9 +1,15 @@
 const num = 56.5678;
-
+console.log(num);
 // You should look up Math functions for this exercise https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math
 
 // Create a variable called wholeNumberPart and assign to it an expression that evaluates to 56 ( the whole number part of num )
 // Create a variable called decimalPart and assign to it an expression that evaluates to 0.5678 ( the decimal part of num )
 // Create a variable called roundedNum and assign to it an expression that evaluates to 57 ( num rounded to the nearest whole number )
 
 // Log your variables to the console to check your answers
+const wholeNumberPart = Math.floor(num);
+console.log("wHole number is:"+ wholeNumberPart);
+const decimalPart = num - wholeNumberPart;
+console.log("decimal part is:"+ decimalPart);
+const roundedNum = Math.round(num);
+console.log("rounded number is:"+ roundedNum);

Sprint-1/exercises/initials.js

@@ -2,5 +2,9 @@ let firstName = "Creola";
 let middleName = "Katherine";
 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 = firstName.charAt(0) + middleName.charAt(0) + lastName.charAt(0);
+
+console.log("initials are:" + initials);

Sprint-1/exercises/paths.js

@@ -10,9 +10,21 @@
 // (All spaces in the "" line should be ignored. They are purely for formatting.)
 
 const filePath = "/Users/mitch/cyf/Module-JS1/week-1/interpret/file.txt";
+console.log(filePath);
 const lastSlashIndex = filePath.lastIndexOf("/");
-const base = filePath.slice(lastSlashIndex + 1);
+console.log(lastSlashIndex);
+const base = filePath.slice(lastSlashIndex+1);
+console.log(base);
 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 = filePath.slice(0,lastSlashIndex+1);
+console.log(dir);
+// Create a variable to store the ext part of the variables.
+const lastDotIndex = filePath.lastIndexOf(".");
+const ext = filePath.slice(lastDotIndex+1);
+console.log(ext);
+
+//another way to extract ext part of filePath string is: 
+const ext2 = filePath.split(".").pop();
+console.log(ext2);

Sprint-1/exercises/random.js

@@ -2,8 +2,12 @@ const minimum = 1;
 const maximum = 100;
 
 const num = Math.floor(Math.random() * (maximum - minimum + 1)) + minimum;
+/*due to rules of precedence, parenthesis executes first. Inside parenthesis, subtraction executes first, 
+then addition executes.*/
+console.log("random number:" + num);
+/*num keeps changing because Math.random() function outputs a different random value between 0 and 1 every time it runs. */
 
-// In this exercise, you will need to work out what num represents?
+// In this exercise, you will need to work out what num represents? answer: a numerical value 
 // 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