并行数组和从文件读取整数/双精度的问题

Question

I have an issue with parallel arrays and getting the program to read integers and doubles. For example, I have a text file with these values:

1234 99.58

5678 1854.99

The first number being an account number and the second number being the balance of the account. I'm not sure how to get them into a parallel array (int[] accountnumber, double[] balance) while going down the list of ideally 10+ accounts and balances.

I've tried filling the arrays separately without success, which doesn't feel like the most efficient method possible. I've tried breaking down the "(int = 0; i < maxAccts; i++)" so I could use the "i" variable for both without resetting it.

    public static int readAccts(int[] acctNum, double[] balance, int maxAccts, File myinput, Scanner inputFile) throws IOException {
    maxAccts = 0;
    while(inputFile.hasNextInt()) {
        //Test for reading integers accurately
        //System.out.println(inputFile.nextInt());
        maxAccts++;
        inputFile.nextLine();}

    //Test for maxAccts
    System.out.println(maxAccts);

    acctNum = new int[maxAccts];
    balance = new double[maxAccts];
    Scanner AccountFiller = new Scanner(myinput);
    while(inputFile.hasNext());{            
    int i = 0;
    while (i < maxAccts) {
            acctNum[i] = AccountFiller.nextInt();
            balance[i] = inputFile.nextDouble();
    i++;}
    //for (int i = 0; i < maxAccts; i++)

    System.out.println(acctNum[1]);}
    return maxAccts;
}

I keep getting this error below:

Exception in thread "main" java.util.NoSuchElementException
at java.util.Scanner.throwFor(Unknown Source)
at java.util.Scanner.next(Unknown Source)
at java.util.Scanner.nextDouble(Unknown Source)

At this point, I don't know why it's going wrong. In my head the cursor in the document should be right after the integer (account number), and I'm not getting an issue with that part.

Answer 1

You might want to fix your while loop

Your second while loop looks like this:

while(inputFile.hasNext());{

Which has a semicolon between the while and the curly brace, which means that the body of the loop is empty and after it is done looping, you run the code inside the curly braces. The loop should be like this:

while(inputFile.hasNext()) {

This causes the error of reading the nextDouble since we just consumed the scanner's source until there is no next.

You might also want to check again how you want to read the file, since the first part doesnt really make much sense to me, it appears you just skip over all ints found in the file (while counting how many times you skip)