Update 3-to-pounds.js

Add detailed comments explaining step-by-step price formatting from pence string.

Author: HoussamLh

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

@@ -1,27 +1,31 @@
 const penceString = "399p";
+// 1. Initializes a string variable with the value "399p" representing the price in pence with a trailing 'p'.
 
 const penceStringWithoutTrailingP = penceString.substring(
   0,
   penceString.length - 1
 );
+// 2. Removes the trailing 'p' by taking a substring from index 0 up to (but not including) the last character.
+//    Result: "399"
 
 const paddedPenceNumberString = penceStringWithoutTrailingP.padStart(3, "0");
+// 3. Ensures the string is at least 3 characters long by padding with leading zeros if needed.
+//    In this case, "399" is already 3 characters, so it remains "399".
+
 const pounds = paddedPenceNumberString.substring(
   0,
   paddedPenceNumberString.length - 2
 );
+// 4. Extracts the pounds part by taking all characters except the last two.
+//    For "399", this is "3" (the hundreds place).
 
 const pence = paddedPenceNumberString
   .substring(paddedPenceNumberString.length - 2)
   .padEnd(2, "0");
+// 5. Extracts the last two characters as the pence part.
+//    For "399", this is "99".
+//    Then pads the string on the right with zeros if it’s shorter than 2 characters (not needed here).
 
 console.log(`£${pounds}.${pence}`);
-
-// This program takes a string representing a price in pence
-// The program then builds up a string representing the price in pounds
-
-// You need to do a step-by-step breakdown of each line in this program
-// Try and describe the purpose / rationale behind each step
-
-// To begin, we can start with
-// 1. const penceString = "399p": initialises a string variable with the value "399p"
+// 6. Prints the formatted price string with a £ sign, pounds, and pence separated by a dot.
+//    Output: "£3.99"