Bubble Sort numbers from file in java

Question

I am trying to bubble sort numbers from a text file, I understand how to bubble sort and how to use a text file. But have never used both of them at the same time. I tried bubble sorting an array and just trying to figure out how to replace that array with a text file. If someone can explain to me how to get the bubble sort to read a text file it would be greatly appreciated. I am new to java and it is sometimes confusing to combine 2 different things I have learned into 1 program.

Here is my bubble sort that solves the array:

  public static void main(String[] args)
 {

  int number[]={7,13,4,5,62,3,1,3,45};

  int temp;
  boolean fixed=false;
  while(fixed==false){
      fixed = true;

  for (int i=0; i <number.length-1;i++){ 
      if (number[i]>number[i+1]){

      temp = number [i+1];

      number[i+1]=number[i];

      number[i]=temp;
      fixed=false;
      }
 }
}
  for (int i=0; i<number.length;i++){
      System.out.println(number[i]);
   }
  }

}

Answer 1

Use Scanner class !

File file=new File("file.txt");
Scanner sc=new Scanner(file);
int arr[]=new int[100];
int i=0;
while(sc.hasNextLine()){
   arr[i]=sc.nextInt();
   i++;
}

Answer 2

Don't just hard code the array..!

Suppose the content of your file is a list of number separated by some delimiter say single space " "

Use:

File file=new File("file.txt");
Scanner sc=new Scanner(file);
String arr[] = sc.nextLine().split(" ");

That is it. Once you have got the array u can play around with it..!

Answer 3

You can do like this:

package test;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Arrays;
import java.util.Scanner;

public class Test {

    public static void bubbleSort(int[] num ) {
        int j;
        boolean flag = true;   // set flag to true to begin first pass
        int temp;   //holding variable

        while ( flag ) {
            flag= false;    //set flag to false awaiting a possible swap
            for( j=0;  j < num.length -1;  j++ ) {
                if ( num[ j ] < num[j+1] )  {
                    temp = num[ j ];                //swap elements
                    num[ j ] = num[ j+1 ];
                    num[ j+1 ] = temp;
                    flag = true;              //shows a swap occurred  
                } 
            } 
        } 
    } 

    public static void main(String[] args) throws FileNotFoundException {
        Scanner scanner = new Scanner(new File("numbers.txt"));
        int [] numbers = new int [256];
        int i = 0;
        while(scanner.hasNextInt()){
           numbers[i++] = scanner.nextInt();
        }

        bubbleSort(numbers);

        System.out.println(Arrays.toString(numbers));

    }
}

Answer 4

Reading a file has nothing to do with bubble sort. You can read the file to create an array of integers and then use the usual bubble sort algorithm to sort it