Assigning values to a 2D array using a nested for loop

Question

I want to iterate values to my 2D array by using a nested for loop but here is what I have so far. I think it does populate my 2D array but not with the numbers I want. I want it to populate with the powers of 2 starting at 2. So my outcome would look like: 2, 4, 8, 16, 32, 64.. and so on until my rows and columns are complete.

My code:

public class RowsSum {
    public static void main(String[] args) {
        int[][] nums = new int[5][3]; //declaring a 2D array of type int
        for (int i = 0; i <= nums.length; i++) {
            for (int j = 0; j < nums[0].length; j++) {
                nums[i][j] = (i * nums[0].length) + j + 1;
                System.out.print(nums[i][j] + "\t");
            }//closing inner loop
            System.out.println("");
        }// closing nested for loop
    }// closing main method
}//closing class

Answer 1

This should work:

public class RowsSum {
  public static void main(String[] args) {
    int[][] nums = new int[5][3]; //declaring a 2D array of type int
    int num = 2;
    for (int i = 0; i < nums.length; i++) {
      for (int j = 0; j < nums[i].length; j++) {
        nums[i][j] = (int) Math.pow(num, ((i*nums[i].length)+j+1)); //code A
        System.out.print(nums[i][j] + "\t");
      }//closing inner loop
      System.out.println("");
    }// closing nested for loop
  }// closing main method
}//closing class

Code A: Here, I just set the value inside the array to 2 to the power of the position in the array, starting from 1. To get the position, I multiply the current col index by the length of each row plus the index in the current row. This is just a way to do it without creating a new count variable outside the loop and then incrementing it every time in the inner loop, although you could do that too if you want to.