Trouble with inputting data from a file

Question

I'm trying to input data from a file that's in the form of

1000
16   11
221   25
234   112
348   102
451   456
183   218
78   338
365   29
114   393
441   369
531   460
...

I'm having trouble because I keep getting IndexOutOfBounds exceptions or NoSuchElement exceptions. How do I put the data into an array so that I can easily sort it later?

 public class shortestRoute { public static void printGrid(int[][] adjMat) { for(int i = 0; i < 1000; i++) { for(int j = 0; j < 2; j++) { System.out.printf("%5d", adjMat[i][j]); } System.out.println(); } } public static void main(String[] args) throws IOException { File file = new File("rtest1-2.dat"); Scanner scanner = new Scanner(file); scanner.useDelimiter("\\\\s+"); int N = scanner.nextInt(); int[][] adjMat = new int[N][2]; for(int i=0; i < N; i++) for (int j=0; j < 2; j++) adjMat[i][j] = scanner.nextInt(); printGrid(adjMat); } } 

Answer 1

You're iterating to much. You have 1000 lines with 2 Integer but you are iterating over 1000x1000 Integer . Just switch the inner for loop to a max of 2:

for(int i=0; i < N; i++){
  for (int j=0; j < 2; j++) {
    adjMat[i][j] = scanner.nextInt();
  }
}

and you should also lower the allocation of your array:

int[][] adjMat = new int[N][2];

Answer 2

 int N = scanner.nextInt();

This will pick up N as 1000. But in the given as example you got only 22 integers and the NoSuchElement errors comes right after 22nd element.

if you provide enough input, then you can get rid of this error. Cheers!