“Introduction to Programming With Java” Lecture - 16 UMESH PATIL (umesh@cse.iitb.ac.in) nlp-ai@cse.iitb

Contents for Today’s Lecture Revision of File-Reading Writing to files Example programs on file handling nlp-ai@cse.iitb

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(); nlp-ai@cse.iitb

FileRead.java nlp-ai@cse.iitb

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(); nlp-ai@cse.iitb

FileWrite.java nlp-ai@cse.iitb

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 nlp-ai@cse.iitb

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 nlp-ai@cse.iitb

ExpandAbbreviation.java nlp-ai@cse.iitb

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. nlp-ai@cse.iitb

End Thank you  nlp-ai@cse.iitb