// class to demonstrate 
// multidimensional arrays
// command line args
public class Array2DDemo {


    // printing a 2D array of ints
    public static void print2D(int[][] grid) {
        // outer loop for rows - length of array of arrays
        for (int [] row : grid) {
            // inner loop for cols - length of individual array
            for (int elt : row) {
                System.out.print(elt+ " ");
            }
            System.out.println(); // newline after row
        }
    }


    // printing a 2D array of strings
    public static void print2D(String[][] grid) {
        // outer loop for rows - length of array of arrays
        for (int i = 0; i < grid.length; i++) {
            // inner loop for cols - length of individual array
            for (int j = 0; j < grid[i].length; j++) {
                System.out.print(grid[i][j]+ " ");
            }
            System.out.println(); // newline after row
        }
    }



    // rectangular array example
    public static void recArrayExample() {
        int [][] rect = new int[2][4];
		// special initialization
        int [][] rect2 = {{1,2},{3,4},{5,6},{7,8}};
		
        int cnt = 1;
		// loop initialization
        for (int i = 0; i < rect.length; i++) {
            for (int j = 0; j < rect[i].length; j++){
                rect[i][j] = cnt++;
            }
        }
        System.out.println("\n Printing 2D array of ints");
        print2D(rect);
        System.out.println("\n Printing 2D array of ints");
        print2D(rect2);
    }

    // example of jagged 2D array
    public static void jaggedArrayExample() {
        // 2D array
        String grd1[][];
        // get space for addresses of 3 String arrays
        grd1 = new String[3][];
        // illegal
        //grd1 = new String[][3];
        //grd1 = new String[][];
		
        // each string array is a different size
        grd1[0] = new String[1];
        grd1[1] = new String[5];
        grd1[2] = new String[3];

		// special initialization
        String [][] grd2 = {{"hello"},{"cat", "dog", "pig"},{"red", "green", "blue", "viridian", "sinople"}};
		
		
        // fill up the array
        // go from 0 to length-1 of array of arrays
        for (int i = 0; i < grd1.length; i++) {
            // go from 0 to length-1 of individual array
            for (int j = 0; j < grd1[i].length; j++) {
                // i, j is the coordinate in the array
                grd1[i][j] = "("+i+", "+j+")";
            }
        }
        // print the result
        System.out.println("\n Printing 2D jagged array of strings");
        print2D(grd1);

        System.out.println("\n Printing 2D jagged array of strings");
        print2D(grd2);

    }


    // main method calls examples
    public static void main(String[] args) {
        // check if there were command line arguments
        if (args != null && args.length > 0) {
            // if r is argument, just do rectangle example
            if (args[0].equals("r")) {
                System.out.println("command line arg: r");
                recArrayExample();
                // any other argument, just do ragged example
            } else {
                System.out.println("command line arg given, not r");
                jaggedArrayExample();
            }
            // if no arguments, do both examples
        } else {
            System.out.println("no command line args given");
			// anonymous 2D array!
			print2D(new int [][] {{1,2,3,4}, {5}, {6, 7, 8}, {9, 10}}); 
            recArrayExample();
            jaggedArrayExample();
        }
    }
}