1. “Introduction to Programming With Java”
Lecture - 16
UMESH PATIL

2. Contents for Today’s Lecture
Revision of File-Reading
Writing to files
Example programs on file handling

3. Revision of File-Reading
Commands for opening the file for reading:
FileReader fr = new FileReader(“input.txt”); BufferedReader br = new BufferedReader(fr);
Command for reading one line from the opened file:
String str = br.readLine();
Command for closing the opened file:
br.close();

4. FileRead.java

5. File-Writing Commands for opening the file for writing:
FileWriter fw = new FileWriter(“output.txt”); BufferedWriter bw = new BufferedWriter(fr);
Command for writing a String to the opened file:
bw.write(str); // str is a String
Command for closing the opened file:
bw.close();

6. FileWrite.java

7. Examples
Write a File-Copy program which copies the content of one file to another. Take both the file names from the user.
Write a Java program for expanding abbreviations in the input text. Store the expanded output in one file. Input text is read from a file. Get the input and output file names from the user. Abbreviations along with their expansions are stored in the file ‘abbreviations.txt’ in the format: <line i>abbreviation <line i+1>expansion

8. ExpandAbbreviation Algorithm
Read abbreviations & expansions from file and store in arrays
Open input file for reading
Open output file for writing
For each line in the input file
Search for each abbreviation in the line and replace if found (find_and_replace() function)
Write the modified line to the output file
Close all opened files

9. ExpandAbbreviation.java

10. Exercise
Write a Java program for reading a dictionary file for counting the no. of dictionary entries in the file. Each line in the file consists of one dictionary entry.

11. End
Thank you 