Added Program-22: Factorial of a Number in Java

Java/Program-22/Program-22.java

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+// Program-22: Factorial of a Number
+
+import java.util.Scanner;
+
+public class Program22 {
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        System.out.print("Enter a number: ");
+        int num = sc.nextInt();
+        long fact = 1;
+
+        if (num < 0) {
+            System.out.println("Please enter a non-negative number.");
+        } else {
+            for (int i = 1; i <= num; i++) {
+                fact *= i;
+            }
+            System.out.println("Factorial of " + num + " is: " + fact);
+        }
+
+        sc.close();
+    }
+}

Java/Program-22/readme.md

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+# Factorial of a Number
+
+## Description
+This program calculates the factorial of a non-negative integer using iteration.
+
+## Input
+- A non-negative integer 
+Example: `5`
+
+## Output
+- Factorial of the number 
+Example: 
+`Factorial of 5 is 120`
+
+## How to Run
+1. Compile using: `javac Program-22.java`
+2. Run using: `java Program22`
+3. Enter a number when prompted.
+4. View the output in the console.