feat: Add Questions2 class with prime and Armstrong number checks

WHAT the code does:
- Defines a `Questions2` class that checks whether a given number (`num = 153`) is:
  1. **Prime** → has no divisors except 1 and itself.
  2. **Armstrong** → sum of digits raised to the power of number of digits equals the number itself.
- Implements both checks without external methods, directly inside `main()`.

WHY this matters:
- Demonstrates fundamental **number theory problems** in Java.
- Reinforces logic building with loops, conditions, and arithmetic operations.
- Avoids using `Math.pow` by implementing power calculation manually, showing low-level control.

HOW it works:
1. **Prime check**:
   - If `num <= 1` → not prime.
   - Otherwise, loops from `2` to `num/2` checking divisibility.
   - If divisible, sets `isPrime = false` and breaks loop.
   - Prints `"Prime"` if no divisors found.
2. **Armstrong check**:
   - Counts number of digits.
   - For each digit, calculates `digit^digits` by repeated multiplication.
   - Sums powered digits and compares with original number.
   - Prints `"Armstrong"` if equal.

Tips & gotchas:
- Prime check could be optimized to loop only till `√num` instead of `num/2`.
- Armstrong logic works for any digit length, not just 3-digit numbers.
- If `num = 1`, code prints nothing (not prime, not Armstrong).
- Using manual power calculation avoids floating-point issues from `Math.pow`.

Use-cases:
- Classic **interview practice problems**.
- Educational demo for beginners learning loops and conditionals.
- Basis for building utility functions for prime/Armstrong checks.
- Can be extended to list all primes or Armstrong numbers in a range.

Short key: algo-prime-armstrong-inline.

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

Author: Someshdiwan

Section10Methods/Methods 2.O/src/Questions2.java

@@ -0,0 +1,47 @@
+public class Questions2 {
+    public static void main(String[] args) {
+        int num = 153; // number to check
+
+        // ---------------- Prime Check ----------------
+        boolean isPrime = true;
+        if (num <= 1) {
+            isPrime = false;
+        } else {
+            for (int i = 2; i <= num / 2; i++) {
+                if (num % i == 0) {
+                    isPrime = false;
+                    break;
+                }
+            }
+        }
+        if (isPrime) {
+            System.out.println("Prime");
+        }
+
+        // ---------------- Armstrong Check ----------------
+        int original = num;
+        int sum = 0, temp = num, digits = 0;
+
+        while (temp > 0) {
+            digits++;
+            temp /= 10;
+        }
+
+        temp = num;
+        while (temp > 0) {
+            int digit = temp % 10;
+            int power = 1;
+
+            // multiply digit "digits" times (instead of Math.pow)
+            for (int i = 0; i < digits; i++) {
+                power *= digit;
+            }
+
+            sum += power;
+            temp /= 10;
+        }
+        if (sum == original) {
+            System.out.println("Armstrong");
+        }
+    }
+}