feat: add FileExample4 to demonstrate reading files with FileReader (character stream)

WHAT:
- Implemented FileExample4 to show how to read text files using FileReader instead of FileInputStream.
- Used try-with-resources for automatic resource management.
- Read the file character by character until end-of-file (`-1`) and printed the output.

WHY:
- FileReader is a character stream, making it more suitable for reading text files compared to byte streams.
- Automatically handles character decoding based on the platform’s default charset.
- Provides a simpler approach for text data compared to manually casting bytes from FileInputStream.

HOW:
1. Opened the file `WithResources.txt` using FileReader inside try-with-resources.
2. Used `fr.read()` to read one character at a time.
3. Printed each character to the console until EOF was reached.

BENEFITS:
- Demonstrates character-based file reading in Java.
- Simplifies handling of text files without manual byte-to-char conversion.
- Ensures proper resource cleanup using try-with-resources.

REAL-WORLD APPLICATIONS:
- Reading configuration files, logs, or structured text data.
- Building simple text processing tools where character decoding is automatically managed.
- Useful in situations where only text files (not binary data) are processed.

NOTES:
- For larger files, `BufferedReader` should be preferred over FileReader alone for efficiency.
- Default charset is platform-dependent; for consistent cross-platform behavior, use `InputStreamReader` with explicit charset.

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

Author: Someshdiwan

Section23JavaIOStreams/src/FileExample4.java

@@ -2,14 +2,44 @@
 
 public class FileExample4 {
     public static void main(String[] args)throws Exception {
-        /*Using Reader and Writer*/
-        try(FileReader fr = new FileReader("C://Users//somes//Downloads//JAVA SE//Section23JavaIOStreams//src//MyJAVA/WithResources.txt");)
+        /* Using Reader and Writer */
+        try(FileReader fr = new FileReader("/Users/somesh/Java SE/JavaEvolution-Learning-Growing-Mastering/Section23JavaIOStreams/src/MyJAVA/WithResources.txt");)
         {
             int x;
-            while((x=fr.read())!=-1)
-            {
+            while((x=fr.read()) != -1) {
                 System.out.print((char)x);
             }
         }
     }
-}
+}
+
+/*
+1. FileReader:
+   - Ye ek character-based input stream hai (text files read karne ke liye best).
+   - Unlike FileInputStream (jo binary/byte read karta hai), FileReader directly characters read karta hai.
+   - Encoding (default platform encoding) handle karta hai → text file ke liye safer option.
+
+2. Important Methods:
+   - fr.read() → ek single character return karega (int form me, -1 if EOF).
+   - fr.read(char[] cbuf) → ek baar me multiple characters ek array me read karega.
+   - fr.close() → stream ko close karta hai (but try-with-resources me auto close ho jaata hai).
+
+3. is program me kya ho raha hai:
+   - FileReader `WithResources.txt` ko open karta hai.
+   - While loop me `fr.read()` se ek-ek character read ho raha hai jab tak -1 (EOF) nahi milta.
+   - `(char)x` cast karke usko console pe print kiya gaya hai.
+
+4. try-with-resources:
+   - Yaha `try(FileReader fr = new FileReader("path"))` likha gaya hai.
+   - Iska fayda: fr.close() automatically call ho jaata hai jab try block finish hota hai.
+
+5. Use Cases:
+   - Text files read karna (letters, words, sentences).
+   - Jab tumhe encoding safe character stream chahiye.
+   - Agar tumhe binary data (images, pdf, audio) read karna ho toh `FileInputStream` use karo.
+
+✔ FileReader = character input stream.
+✔ read() → char by char data read karta hai.
+✔ Best for text files (not binary).
+✔ try-with-resources = auto close, no memory leaks.
+*/