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I am supposed to read points from a file and accept those points as an array so that I can implement Grahams Scan, however my program only seems to accept the first line of points can anyone help?

import java.io.*;
import java.util.*;

public class Graham {

private static int[] get_arr(String input) throws Exception
{
    String squirtle;
    String[] wartortle;
    int[] arr;

    //Gets the file
    BufferedReader in = new BufferedReader(new FileReader(input));
    squirtle = in.readLine();

    //delimits numbers with a comma  for eventual output
    wartortle = squirtle.split(",");

    arr = new int[wartortle.length];

    //parses values into array
    for (int i = 0; i < wartortle.length; i++)
    {
        arr[i] = Integer.parseInt(wartortle[i]);
    }
    return arr;

}

public static void main(String[] args) throws Exception
{
    //initializes answer which is used to see if the user wants to repeat the prgm
    String answer;
    do
    {
        String input;
        int[] arr;
        Scanner scanner = new Scanner(System.in);

        System.out.println("Please enter a source filename such as C:\\Users\\user_\\Documents\\file.txt, or if it's in the same folder as this class just file.txt");
        input = scanner.next();

        System.out.println("The points");

        //Used for outputting file contents
        BufferedReader br = new BufferedReader(new FileReader(input));
        String line;
        while ((line = br.readLine()) != null)
        {
            System.out.println(line);
        }
        //Gather array
        arr = get_arr(input);

        //Prints array
        System.out.println(Arrays.toString(arr));

        System.out.println("Thank you for using this program, if you would like to run it again press y if not press anything else");
        answer = scanner.next();
    }
    //whenever the user inputs y the program runs again
    while (answer.equals("y")) ;
}

}

my text file called garr.txt looks like 
1,2
2,3
3,4
4,5
5,6

But only accepts 1,2

IcySun
  • 15
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1 Answers1

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The problem in the code is you read only single line from your input file. You should read all lines from the file. You can Change get_arr method as follows:

private static Integer[] get_arr(String input) throws Exception
{
    String squirtle;
    List<Integer> intList = new ArrayList<Integer>();

    //Gets the file
    BufferedReader in = new BufferedReader(new FileReader(input));

    while((squirtle = in.readLine()) != null) { //Reads all lines
         //delimits numbers with a comma  for eventual output
        String[] wartortle = squirtle.split(",");

        for (int i = 0; i < wartortle.length; i++)
        {
            intList.add(Integer.parseInt(wartortle[i]));
        }
    }

    return intList.toArray(new Integer[0]); //converts Integer list to int[]
}
Kamil Akhuseyinoglu
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