feat: implement file copy with uppercase-to-lowercase transformation using streams

Overview
Added SCIO1 program demonstrating Java file I/O using FileInputStream and FileOutputStream.
The program copies content from one file to another while converting uppercase letters to lowercase during the transfer.

Implementation Details
Input stream (FileInputStream): Reads bytes sequentially from the source file (Source1.txt). File must exist before execution.
Output stream (FileOutputStream): Writes processed bytes into the destination file (Source3.txt). If the file exists, it will be overwritten.
Processing logic:
- Data is read one byte at a time (fis.read()), returning -1 at EOF.
- Each byte is checked against the ASCII range 65–90 (uppercase A–Z).
- If the condition matches, 32 is added to the byte to convert it into the corresponding lowercase character.
- Otherwise, the original byte is written unchanged.
Resource management: Both input and output streams are explicitly closed to release system resources and avoid memory leaks.

Key Learning Points
Demonstrates low-level byte stream operations in Java.
Shows how to transform data while streaming from one file to another.
Reinforces understanding of ASCII-based character manipulation.
Highlights the importance of explicitly closing I/O streams.

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

Author: Someshdiwan

Section23JavaIOStreams/src/MyJAVA/Source1.txt

@@ -1 +1 @@
-COPYING THIS FILE INTO ANOTHER FILE.
+COPYING THIS FILE INTO ANOTHER FILE. and converting the lower case to an upper case letter.

Section23JavaIOStreams/src/MyJAVA/Source3.txt

@@ -1 +1 @@
-copying this file into another file.
+copying this file into another file. and converting the lower case to an upper case letter.

Section23JavaIOStreams/src/SCIO1.java

@@ -3,16 +3,50 @@
 
 public class SCIO1 {
     public static void main(String[] args) throws Exception {
-        FileInputStream fis = new FileInputStream("C://Users//somes//Downloads//JAVA SE//Section23JavaIOStreams//src//MyJAVA//Source1.txt"); //Must Be created file.
-        FileOutputStream fos = new FileOutputStream("C://Users//somes//Downloads//JAVA SE//Section23JavaIOStreams//src//MyJAVA//Source3.txt");
+        FileInputStream fis = new FileInputStream("/Users/somesh/Java SE/JavaEvolution-Learning-Growing-Mastering/Section23JavaIOStreams/src/MyJAVA/Source1.txt");
+        //Must Be created file.
+
+        FileOutputStream fos = new FileOutputStream("/Users/somesh/Java SE/JavaEvolution-Learning-Growing-Mastering/Section23JavaIOStreams/src/MyJAVA/Source3.txt");
 
         int b;
-        while((b= fis.read())!=-1)
+        while((b = fis.read())!=-1)
         {
-            if(b>=65 && b<=120)fos.write(b+32);
-            else fos.write(b);
+            if (b >= 65 && b <= 90) // 'A' to 'Z'
+                fos.write(b + 32);   // Convert uppercase to lowercase
+            else
+                fos.write(b);
         }
         fis.close();
         fos.close();
     }
-}
+}
+
+/*
+1. FileInputStream (fis):
+   - Source file (`Source1.txt`) se byte-by-byte data read karta hai.
+   - Har ek character ko ASCII value ke form me deta hai.
+
+2. FileOutputStream (fos):
+   - Target file (`Source3.txt`) me data write karta hai.
+   - Jo bhi byte likhte ho, wahi directly file me save hota hai.
+
+3. Logic (Transformation Part):
+   - `if (b >= 65 && b <= 90)` → Ye ASCII range uppercase letters (A–Z) ko represent karti hai.
+   - Agar character uppercase hai toh `b + 32` karke lowercase me convert hota hai.
+     - Example: 'A' (65) + 32 = 'a' (97), 'B' → 'b', ... 'Z' → 'z'.
+   - Agar uppercase nahi hai, toh byte as-it-is copy hota hai.
+
+4. Close Streams:
+   - `fis.close(); fos.close();` → Input/output streams properly close karna zaroori hai.
+   - Ye ensure karta hai ki resources release ho jayein aur file corruption na ho.
+
+5. Output Behavior:
+   - Source file se uppercase letters convert hoke lowercase ban jaayenge.
+   - Baaki characters (digits, spaces, symbols, lowercase) unchanged rahenge.
+
+✔ FileInputStream → file se data read karta hai (byte-by-byte).
+✔ FileOutputStream → file me data write karta hai.
+✔ Logic → uppercase letters ko lowercase me convert karta hai.
+✔ Program ek file copy + case transformation ka simple example hai.
+✔ Useful for preprocessing text files (e.g., normalize data to lowercase).
+*/