feat: Demonstrate string comparison and concatenation methods in Java

📌 Highlights:
- Compare strings using:
  - `equals()` — case-sensitive comparison.
  - `equalsIgnoreCase()` — case-insensitive comparison.
  - `==` — compares object references (not recommended for content comparison).
- Use `compareTo()` to perform lexicographical comparison.
- Use `contains()` to check for a substring.
- Concatenate strings using `concat()` and `+`.

🔍 Examples:
- `"Pyramid".equals("pyramid")` → false
- `"Pyramid".equalsIgnoreCase("pyramid")` → true
- `"china wall".compareTo("china tall")` → returns a positive value since `'w' > 't'`
- `"the great wall".contains("wall")` → true
- `"the great wall".concat("of china")` → combines both strings

✅ Purpose:
To explore key string operations used in real-world Java programs such as comparisons, substring checks, and joining.

Signed-off-by: Somesh diwan <[email protected]>

Author: Someshdiwan

Section6StringClassPrinting/src/StringAB5.java

@@ -1,5 +1,4 @@
 public class StringAB5 {
-
     public static void main(String[] args) {
 
         String str1="Pyramid";
@@ -24,8 +23,5 @@ public static void main(String[] args) {
         System.out.println(str1.contains("wall"));
         System.out.println(str1.concat(str2));
         System.out.println(str1 + str2);*/
-
-
     }
-
-}
+}