feat: add CharArrayReader example to read characters from array.

WHAT:
- Implemented `CharArrayReaderExample` demonstrating the use of `CharArrayReader`.
- Created a character array containing the English alphabet (a–z).
- Used `CharArrayReader` to sequentially read characters from the array.
- Printed each character to the console until end-of-stream (-1) was reached.

WHY:
- `CharArrayReader` is a specialized character stream in Java that allows
  treating a character array as a source of input (like a file or network stream).
- Useful for testing, prototyping, or processing text data without needing
  actual I/O resources.

HOW:
1. Defined a `char[]` array with values 'a' through 'z'.
2. Initialized `CharArrayReader` with the array, making it behave like a reader stream.
3. Invoked `read()` in a loop until `-1` (EOF) was returned.
4. Printed characters to verify proper reading.

REAL-WORLD USE CASES:
- Simulating file or network input when working with in-memory character data.
- Parsing strings or character arrays using APIs that expect a `Reader`.
- Testing algorithms that work on `Reader` streams without needing files.
- Useful in scenarios like templating engines or XML/JSON parsers where
  in-memory text is processed as if it were a stream.

NOTES:
- Unlike `FileReader`, `CharArrayReader` does not involve any disk I/O.
- Supports `mark()` and `reset()` operations, allowing re-reading of sections.
- Often paired with `CharArrayWriter` when both reading and writing
  in-memory character data is required.

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

Author: Someshdiwan

Section23JavaIOStreams/src/CharArrayReaderExample.java

@@ -8,4 +8,31 @@ public static void main(String[] args)throws Exception {
             System.out.print(" "+(char)x);
         }
     }
-}
+}
+
+/*
+1. CharArrayReader:
+   - Ye ek subclass hai Reader ka (java.io.Reader).
+   - Ek `char[]` ko input stream ke tarah treat karta hai.
+   - Matlab file ke jagah directly ek array se read kar sakte ho.
+
+2. Constructor:
+   - `CharArrayReader(char[] buf)` → poora character array ko Reader banata hai.
+   - `CharArrayReader(char[] buf, int offset, int length)` → sirf ek portion ko Reader banata hai.
+
+3. Code Flow:
+   -  Ek char array `{'a','b',...,'z'}` banaya.
+   - `CharArrayReader car = new CharArrayReader(c);` → ab car stream jaisa behave karega.
+   - `car.read()` ek ek karke characters deta hai (int return hota hai, isliye typecast `(char)x` kiya).
+   - Jab saare characters read ho jaye → `read()` -1 return karega.
+
+4. Use Cases:
+   - Jab tumhare paas already memory me `char[]` data ho aur tum usko stream ke tarah process karna chahte ho.
+   - FileReader jaisa hi use hota hai, par source file ke bajay in-memory array hota hai.
+   - Useful testing ke liye (jaise parsers, scanners, etc.).
+
+
+✔ CharArrayReader ek char[] ko Reader banata hai.
+✔ read() ek ek char deta hai jab tak array khatam na ho.
+✔ FileReader ka in-memory alternative.
+*/