import java.io.File;
import java.io.FileWriter;

/**
 * Here's some sample code that creates a text file and writes a couple of lines
 * of text to it. There are some hints in the comments below about what you'll
 * need to change if you want to work with binary data instead of just strings.
 * Also, note that I don't do any error-checking in the body of the code -- I
 * just label main as "throws Exception" so it becomes somebody else's problem.
 * You'll need to do better than that for the assignment.
 * 
 * @author brichards
 */

public class FileExample {
    public static void main(String[] args) throws Exception {
        // Get the filename, either as a command-line argument or the default.
        String filename = "textfile.txt";
        if (args.length > 0) {
            filename = args[0];
        }

        // Create a new File object, though it doesn't necessarily correspond 
        // to an actual file on the disk.
        File theFile = new File(filename);
        
        // Now see if it's already there...
        if (theFile.exists()) {
            System.out.println("It already exists. Contents will be overwritten");
        }
        else {
            System.out.println("Creating new file: "+theFile.getAbsolutePath());
        }

        // File objects don't have read or write methods. Instead, we have to
        // create some sort of "writer" stream and associate it with the file.
        // Here I'm using a FileWriter, which is great for strings but not so
        // great for binary data. You'll want to check out FileOutputStream,
        // and find a write() method that lets you specify how many bytes from
        // an array of bytes are to be written. (That same approach will work 
        // for both text and binary data.)
        FileWriter writer = new FileWriter(theFile);
        writer.write("hello\n");
        writer.write("world");
        writer.close();
    }
}