Creating Ouput Text File

[Raian]

I'm having trouble with how to generate 10 random numbers between 50 and 100 and write them to a text file.

this is what i got so far..i'm stuck at the part: output to a text file
Please help me, give me some ideas or advice on how to fix it or doing it.
Thanks in advance.

import java.io.*;
import java.util.Random;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;

public class Project7PartB {

   public static void main(String args[])
        {              
                FileOutputStream out; // declare a file output object
                
                try
                {
                	
						// Create a new file output stream
                        // connected to "myfile.txt"
                        out = new FileOutputStream("myfile.txt");

                        // Connect print stream to the output stream
                        Rand = new PrintStream( out );
                        Random randomnumber = new Random();
						int yes[] = new int[10];
						for(int i=0; i < 10; i++) {
						yes[i] = randomnumber.nextInt(51) + 50;
						System.out.println(yes[i]);
						}
                }
                
                catch (Exception e){
                        System.err.println ("Error writing to file");
                }
        }
}

Moderator Edit: Code tags added

[Fubarable]

Hello, and welcome to the forum. I hope you don't mind that I edited your code and added code tags which should help make your posted code retain its formatting and be more readable.

To do this yourself, highlight your pasted code (please be sure that it is already formatted when you paste it into the forum; the code tags don't magically format unformatted code) and then press the code button, and your code will have tags.

Another way to do this is to manually place the tags into your code by placing the tag [code] above your pasted code and the tag [/code] below your pasted code like so:

[code]
  // your code goes here
  // notice how the top and bottom tags are different
[/code]

Best of luck, and again, welcome!

[Fubarable]

Have a look at the Sun input and output tutorials which you can find here: Lesson: Basic I/O

In particular, check out the sections on character output.

Much luck!

[cselic]

import java.util.Random;

import java.io.FileWriter;
import java.io.BufferedWriter;
import java.io.IOException;

public class Project7 {
	
	static final String fileName = "myfile.txt";
	
	public static void main(String[] args) {
		try {
		BufferedWriter writer = new BufferedWriter(new FileWriter(fileName));
		 Random randomNumber = new Random();
		 int[] yes = new int[10];
		 String value;
		 for(int i = 0; i < 10; i++) {
			 yes[i] = randomNumber.nextInt(51) + 50; 
			 value = Integer.toString(yes[i]);
			writer.write(value + " ");
			}
		 writer.close();
		
		} catch(IOException e) {
			e.printStackTrace();
			System.exit(1);
			} 
	}
}

[erakhman]

import java.io.*;
import java.util.Random;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;

public class Project7PartB {

	public static void main(String args[]) {

		FileOutputStream out; // declare a file output object
		PrintStream Rand; // declare variable Rand
		try {
			// Create a new file output stream
			// connected to "myfile.txt"
			out = new FileOutputStream("myfile.txt");
			// Connect print stream to the output stream
			Rand = new PrintStream( out );
			Random randomnumber = new Random();
			int yes[] = new int[10];
			for(int i=0; i < 10; i++) {
				yes[i] = randomnumber.nextInt(51)+ 50;
				System.out.println(yes[i]); // Write output to consule 
				Rand.println(yes[i]); // Write output to file 
			}
		}
		catch (Exception e){
			System.err.println ("Error writing to file");
		}

	}

}

[Fubarable]

cselic closes his writer but erakhman doesn't. This may seem like a small point, but if you have enough of this sort of thing going on in a program, you'll risk running out of resources. I would recommend to both that the BufferedWriter be closed in a finally block after checking that it's not null.

[cselic]

Well, I have problem with finally block.

if I write something like this:

} catch(IOException e) {
			e.printStackTrace();
			System.exit(1);
			} finally {
				writer.close();
			}
	}

Then I have error:
"The local variable writer may not have been initialized
Unhandled exception type IOException"

[erakhman]

cselic closes his writer but erakhman doesn't. This may seem like a small point, but if you have enough of this sort of thing going on in a program, you'll risk running out of resources. I would recommend to both that the BufferedWriter be closed in a finally block after checking that it's not null.

Thanks moderator, now i have completed my code :

import java.io.*;
import java.util.Random;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;

public class Project7PartB {

	public static void main(String args[]) {

		FileOutputStream out=null; // declare a file output object
		PrintStream Rand; // declare variable Rand
		try {
			// Create a new file output stream
			// connected to "myfile.txt"
			out = new FileOutputStream("myfile.txt");
			// Connect print stream to the output stream
			Rand = new PrintStream( out );
			Random randomnumber = new Random();
			int yes[] = new int[10];
			for(int i=0; i < 10; i++) {
				yes[i] = randomnumber.nextInt(51)+ 50;
				System.out.println(yes[i]); // Write output to consule 
				Rand.println(yes[i]); // Write output to file 
			}
		}
		catch (Exception e){
			System.err.println ("Error writing to file");
		}
		finally {
			try {
				out.close(); // Close file
			}
			catch (Exception e) {
				System.err.println ("Error close file");
			}
		}

	}

}

[Fubarable]

Thanks moderator, now i have completed my code :

Sorry for nit-picking, and I'm no pro at this either, but I'd still modify this further by checking that out isn't null first before closing it and would try to use the most specific exception possible:

    try {

      //...... code deleted for sake of brevity

    } catch (FileNotFoundException e) {
      System.err.println("Error writing to file");
      e.printStackTrace();
    } finally {
      try {
        if (out != null) {
          out.close();
        }
      } catch (IOException e) {
        e.printStackTrace();
      }
    }

As always, corrections are most welcome!

[erakhman]

Ok, i think you're right, thanks ya...

[cselic]

Code:
    try {

      //...... code deleted for sake of brevity

    } catch (FileNotFoundException e) {
      System.err.println("Error writing to file");
      e.printStackTrace();
    } finally {
      try {
        if (out != null) {
          out.close();
        }
      } catch (IOException e) {
        e.printStackTrace();
      }
    }

On this way my compiler continue to report an error, and requires writting another IOException.
Something like this:

try {

} catch(FileNotFoundException e) {

} [B][COLOR="Purple"]catch(IOException e) {
}[/COLOR][/B] finally {
      try {
        if (out != null) {
          out.close();
        }
      } catch (IOException e) {
        e.printStackTrace();
      }
    }

[Fubarable]

Don't leave your catch block empty unless you are the type that enjoys driving a car with blindfolds on.

[cselic]

Don't leave your catch block empt

I don't leave them empty. I did it for simplicity ;)
Sorry.

Complete code:

} catch (FileNotFoundException e) {
		      System.err.println("Error writing to file");
		      e.printStackTrace();
		    } [B][COLOR="Navy"]catch(IOException e) {
		    	e.printStackTrace();
		    }[/COLOR][/B] finally {
		      try {
		        if (writer != null) {
		          writer.close();
		        }
		      } catch (IOException e) {
		        e.printStackTrace();
		      }
		    }

[erakhman]

try edit your code, like this :

public static void main(String[] args) {
		BufferedWriter writer = null;
		try {
		writer = new BufferedWriter(new FileWriter(fileName));

[cselic]

try edit your code, like this

Code is already written on that way. And it still need another catch with IOException.
I think it's much better to me to take care of one more exception. :cool: