将.txt文件中的数据存储到数组中并创建等级

Question

I'm trying to use data from a txt file to populate an array. Essentially, I don't understand what the structure of the loop code needs to be. I understand that the index needs to be treated like an int variable in the loop, but I don't know what that looks like.

This is what I have so far and it's very wrong,

public class ReadTextFileUsingScanner
{

    public static void main(String[] args) throws Exception 
    {
        String[] snumArray;
        snumArray = new String[1000];

        double[] gpaArray;
        gpaArray = new double[1000];

        int rank = 0;
        double currentGPA = 4.1;



        Scanner gpadata = new Scanner(new File("studentdata.txt"));

        while (gpadata.hasNext())
        {
            snumArray[0] = gpadata.next();
            gpaArray[0] = gpadata.nextDouble();

            if (currentGPA > gpaArray[0])
            {
                rank++;
            }

            System.out.println(snumArray[0] + "\t" + gpaArray[0] + "\t" + rank);

        }
    }


}

I'm only a couple months into java programming and I've really hit a brick wall with this. I need my output to look like this:

S316542                3.45        27
S29463                  1.42        801
S969870                2.75        T64 with 8 others

And I can't change the order of the students so I can't use sort to create the rank.

All I really want to know though, is how do I populate the index with data from the .txt file? The way I'm doing it now (is stupid, I know) is only ever populating the [0] index then printing, then replacing the data at the [0] index. That's not right. I've spent probably a good 5 hours searching the internet for ANYTHING like this and there are TONS of similar questions out there but I can't understand any of the answers at all. Can someone just show me what that code structure would be?

Answer 1

You can just make an int line variable and iterate at the end of the loop

Then, you want to check lines from the Scanner; .next() only reads to the next whitespace.

   Scanner gpadata = new Scanner(new File("studentdata.txt"));
   int line = 0; // Add this
   while (gpadata.hasNextLine()) {
        String[] columns = gpadata.nextLine().split("\t");

        snumArray[line] = columns[0];
        gpaArray[line] = Double.parseDouble(columns[1]);

        if (currentGPA > gpaArray[line]) {
            rank++;
        }

        System.out.println(snumArray[line] + "\t" + gpaArray[line] + "\t" + rank);

        line++; // Add this
    }
}