Thread: ReadWrite program advise

Hi all...I have this program that I wrote that creates a random number, writes it to a file and scans it back to the system. That part alone took me forever to hash out. Now I stuck. I would like to create 100 random integers and sort them in both the file and the printout.

Here is the code

   import java.util.Random;
   import java.util.Scanner;
   public class ReadWriteData {
 
    // Main method
      public static void main (String[] args)throws Exception {
 
       //Create a file instance
         java.io.File file = new java.io.File("100 random  sorted numbers txt.");
 
         if (file.exists()) {
            System.out.println("File Already Exists");
            System.exit(0);
 
         }
 
         //Create a file
         java.io.PrintWriter output = new java.io.PrintWriter(file);
 
      	//Create ramdom number to be sorted
         Random randomGenerator = new Random();
 
         //Write formatted output to the file
         output.println(randomGenerator.nextInt(100));
 
         //close the output file
         output.close();
 
         //Create a Scanner for the file
         Scanner input = new Scanner(file); 
 
         //Read data from a file
         while (input.hasNext()) {
 
            int score = input.nextInt();
            System.out.println(
                  score);
         }
 
         //Close the input file
         input.close();    
      }
   }

Could someone advise me on the logic and code placement needed to pull this off?

Well I corrected my code to print and write 100 integers. On the other hand I'm completely stumped about how to sort it. Help me please!

Do I need an array? Where should that code go if I do? If not, then what?

   import java.util.Random;
   import java.util.Scanner;
   public class ReadWriteData {
 
    // Main method
      public static void main (String[] args)throws Exception {
 
       //Create a file instance
         java.io.File file = new java.io.File("100 random  sorted numbers txt.");
 
         if (file.exists()) {
            System.out.println("File Already Exists");
            System.exit(0);
 
         }
 
         //Create a file
         java.io.PrintWriter output = new java.io.PrintWriter(file);
 
      	//Create ramdom number to be sorted
         Random randomGenerator = new Random();
 
         for (int i = 0; i < 100; i++) {
 
         //Write formatted output to the file
            output.println(randomGenerator.nextInt(100));
         }
 
         //close the output file
         output.close();
 
         //Create a Scanner for the file
         Scanner input = new Scanner(file); 
 
         //Read data from a file
         while (input.hasNext()) {
 
            int score = input.nextInt();
            System.out.println(
                  score);
         }
 
         //Close the input file
         input.close();    
      }
   }

I'm almost there. I decided to use my own class to sort but it's not working. It might be the placement.

Take a look...

   import java.util.Random;
   import java.io.*;
 
   public class ReadWriteSort {
 
    //Creates an exception
      public static void main (String [] args)throws IOException { 
 
       //Assigns the variable digit as a random number
         Random digit = new Random();
 
       //Array with 100 numbers
         int list[] = new int[100];
         File file = new File("Exercise9_19.txt");
 
         if (file.exists()){
            System.out.println("The file " + file.getName() + " already exists.");
            System.out.println();
 
 
         }//ends if statement
 
         else {
 
            System.out.println("Your file has been written to " + (file.getName()+ "."));
            System.out.println();
         }
 
         try {
 
            Writer output = null;
 
          //Name of txt file
            File x = new File("Exercise9_19.txt");
            output = new BufferedWriter(new FileWriter(x));
 
          //for loop to create 100 random numbers
            for (int i = 0; i < list.length; i++) {
 
             //Set an array of random numbers with a range of 0 - 100 
               list[i] = (digit.nextInt(100));       
 
             //output is the array of random numbers  
               output.write(list[i]+" "); 
 
            }//ends for loop
 
            SelectionSort.selectionSort(list);//THIS MY BE MY PROBLEM!
 
          //ends output
            output.close();
 
            FileInputStream fstream = new FileInputStream("Exercise9_19.txt");
 
         // Get the object of DataInputStream
            DataInputStream input = new DataInputStream(fstream);
            BufferedReader br = new BufferedReader(new InputStreamReader(input));
            String strLine;
 
          //Read File Line By Line
            while ((strLine = br.readLine()) != null) {
 
            // Print the content on the console
               System.out.println (strLine);
            }
         //Close the input stream
            input.close();
 
         }//ends try
 
            //If there is no file
            catch (IOException e) {
               System.err.println("The file was not saved.");
               e.printStackTrace();
 
            }//ends catch
 
      }
 
    //Selction sort method
      public static class SelectionSort {
 
         static void selectionSort(int list[]) {
 
            for (int i = 0; i < list.length - 1; i++) {
               int currentMin = list[i];
               int currentMinIndex = i;
 
               for( int j = i + 1; j < list.length - 1; j++) {
                  if (currentMin > list[j]){
                     currentMin = list[j];
                     currentMinIndex = j;
                  }
               }
               if (currentMinIndex != i ){
                  list[currentMinIndex] = list[i];
                  list[i] = currentMin;
 
               }
            }
         }    
      }
   }//ends class

Please show me the way of my error!

1. Use list instead of array and use it's built in sort.
2. I mean to say, first put all random numbers in the list, sort them and place them in the file.