Java ASCII output to file

[jmace]

When I try to output an ASCII value to a file, it sometimes writes the wrong value. Example:

import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.PrintWriter;

public class test {
	public static void main(String args[]){
		                          //Supposed to:
		writeFile("./test.txt"); //write ASCII 147
		readFile("./test.txt"); //read ASCII 147
	}
	
	public static boolean writeFile(String path){
		try{
			PrintWriter fo = new PrintWriter(new FileOutputStream(new File(path)));
			fo.print((char) 147); //WRITES "?" TO FILE (ASCII 63, NOT 147)
			fo.close();
		}catch(Exception e){
			return true;
		}
		return false;
	}
	
	public static boolean readFile(String path){
		try {
			BufferedReader fi = new BufferedReader(new FileReader(path));
			char c[] = fi.readLine().toCharArray();
			System.out.println((int) c[0]); //OBVIOUSLY PRINTS 63 INSTEAD OF 147
			fi.close();
			return true;
		} catch (Exception e){
			e.printStackTrace();
			return false;
		}
	}
}

What am I doing wrong? Any help would be great.

[DavidKroukamp]

When I try to output an ASCII value to a file, it sometimes writes the wrong value. Example:

import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.PrintWriter;

public class test {
	public static void main(String args[]){
		                          //Supposed to:
		writeFile("./test.txt"); //write ASCII 147
		readFile("./test.txt"); //read ASCII 147
	}
	
	public static boolean writeFile(String path){
		try{
			PrintWriter fo = new PrintWriter(new FileOutputStream(new File(path)));
			fo.print((char) 147); //WRITES "?" TO FILE (ASCII 63, NOT 147)
			fo.close();
		}catch(Exception e){
			return true;
		}
		return false;
	}
	
	public static boolean readFile(String path){
		try {
			BufferedReader fi = new BufferedReader(new FileReader(path));
			char c[] = fi.readLine().toCharArray();
			System.out.println((int) c[0]); //OBVIOUSLY PRINTS 63 INSTEAD OF 147
			fi.close();
			return true;
		} catch (Exception e){
			e.printStackTrace();
			return false;
		}
	}
}

What am I doing wrong? Any help would be great.

maybe you must set the default encoding to ascii:http://stackoverflow.com/questions/361975/setting-the-default-java-character-encoding on my Netbeans the code gives me '"'
you could also try:

FileInputStream fis =  new FileInputStream("out.dat");
      BufferedReader r = 
        new BufferedReader(new InputStreamReader(fis, "ACSII"));

when attempting to read and write

[jmace]

Thanks for the suggestion. I'm playing around with it, but I still haven't figure it out...

[hiddepolen]

See the screenshot, I get a value of 147! No change in your code...

PS, What do you mean by 'sometimes'? Usually programs give the same output, whether you run them once or 100 million times...

[jmace]

Strange. That's not the results that I am getting.

By "sometimes," I meant "for some values." Sorry for my lack of clarity. For most ASCII values the correct number is returned, but for a few-- like 147-- it's wrong.

[hiddepolen]

Very interesting. What IDE, OS and Java version are you using?
Maybe a good idea to post this on StackOverflow, there are a lot of experts, who know really ANYTHING about ANY coding questions.

[JamesCherrill]

I hate to rain on your parade, but there's no such thing as an ASCII value of 147.
The ANSI ASCII standard code is a 7 bit code, covering values 0 - 127.
There are many many variants on 8 bit codes (code pages in DOS terms), which are consistent with ASCII up to 127 the go their own ways 128-255.
Java uses Unicode, which is a 16 bit code that us consistent with ASCII for values where the first 9 bits are all zero.
When you convert a Unicode value in the range 128-255 to/from an 8 bit value you are at the mercy of whatever code page(s) may be used by your system at the time.
http://en.wikipedia.org/wiki/ASCII

[jmace]

So the question remains: how can I output the character-casted 147 to a file and read in the integer-casted number of the character.

[JamesCherrill]

My best guess would be some variant of the solutions discussed in cOrRuPtG3n3t!x's link above (and also see http://docs.oracle.com/javase/tutorial/i18n/text/stream.html
or to convert String to/from byte array explicitly in your code and read/write the byte arrays.
http://docs.oracle.com/javase/tutorial/i18n/text/string.html