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Introduction to Programming With Java
Lecture - 16 UMESH PATIL (umesh_at_cse.iitb.ac.in)
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Contents for Todays Lecture

• Revision of File-Reading
• Writing to files
• Example programs on file handling

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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()

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FileRead.java
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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()

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FileWrite.java
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Examples

1. Write a File-Copy program which copies the
   content of one file to another. Take both the
   file names from the user.
2. 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
   formatltline igtabbreviationltline i1gtexpansion

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ExpandAbbreviation Algorithm

1. Read abbreviations expansions from file and
   store in arrays
2. Open input file for reading
3. Open output file for writing
4. For each line in the input file
5. Search for each abbreviation in the line and
   replace if found(find_and_replace() function)
6. Write the modified line to the output file
7. Close all opened files

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ExpandAbbreviation.java
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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.

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End
Thank you ?
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