feat: Implement auto-generated student roll numbers using static counter and date-based prefix

WHAT the code does:
- Defines StudentName class:
  - Private field rollNo stores the unique identifier for each student.
  - Static counter count starts at 1 and increments with each new object.
  - Private method assignRollNo():
    - Uses java.util.Date to fetch the current year.
    - Constructs roll number as "University-<year>-<count>".
    - Increments count for the next student.
  - Constructor assigns rollNo by calling assignRollNo().
  - Public getter getRollNo() returns the roll number.
- Defines main class ToughStaticSolveIt:
  - Creates three StudentName objects (s1, s2, s3).
  - Prints their generated roll numbers.

WHY this matters:
- Demonstrates **static variable usage** for generating unique sequential identifiers shared across all instances.
- Shows how to combine static state with dynamic data (current year from Date) to generate meaningful roll numbers.
- Ensures each student object gets a unique roll number without requiring manual input.

HOW it works:
1. First StudentName object:
   - count = 1 → assigns "University-2025-1".
   - count increments to 2.
2. Second StudentName object:
   - count = 2 → assigns "University-2025-2".
   - count increments to 3.
3. Third StudentName object:
   - count = 3 → assigns "University-2025-3".
   - count increments to 4.
4. Printing confirms unique sequential roll numbers.

Tips and gotchas:
- java.util.Date.getYear() is deprecated; prefer java.time.LocalDate.now().getYear() for modern code.
- Static counter resets only when JVM restarts; persistence across sessions would require external storage (file, database).
- Class and method naming could follow Java conventions:
  - StudentName → Student
  - ToughStaticSolveIt → RollNumberGeneratorDemo
- Making assignRollNo() private ensures roll numbers are controlled internally, enforcing encapsulation.

Use-cases / analogies:
- Similar to how universities or organizations auto-generate IDs for students, employees, or tickets.
- Like a bakery numbering receipts: each new customer gets the next number, prefixed with the current year.

Short key: java static-counter unique-id auto-generated roll-numbers encapsulation.

Signed-off-by: https://github.com/Someshdiwan <[email protected]>

Author: Someshdiwan

Section16StaticFinal/src/Car.java

@@ -1,25 +1,23 @@
 import java.util.Date;
 
-class StudentName
-{
+class StudentName {
     private String rollNo;
 
     private static int count=1;
 
-    private String assignRollNo()
-    {
+    private String assignRollNo() {
         Date d = new Date();
 
         String rno="University-"+(d.getYear()+1900)+"-"+count++;
 
         return rno;
     }
-    StudentName()
-    {
+
+    StudentName() {
         rollNo=assignRollNo();
     }
-    public String getRollNo()
-    {
+
+    public String getRollNo() {
         return rollNo;
     }
 }
@@ -34,4 +32,4 @@ public static void main(String[] args) {
         System.out.println(s2.getRollNo());
         System.out.println(s3.getRollNo());
     }
-}
+}