Program to print the elements of a 2d array in the form of a matrix in spiral form.

// Java program to print a given matrix in spiral form
import java.io.*;
 
class GFG {
 
    // Function print matrix in spiral form
    static void spiralPrint(int m, int n, int a[][])
    {
        int i, k = 0, l = 0;
 
        /*  k - starting row index
        m - ending row index
        l - starting column index
        n - ending column index
        i - iterator
        */
 
        while (k < m && l < n) {
            // Print the first row from the remaining rows
            for (i = l; i < n; ++i) {
                System.out.print(a[k][i] + " ");
            }
            k++;
 
            // Print the last column from the remaining
            // columns
            for (i = k; i < m; ++i) {
                System.out.print(a[i][n - 1] + " ");
            }
            n--;
 
            // Print the last row from the remaining rows */
            if (k < m) {
                for (i = n - 1; i >= l; --i) {
                    System.out.print(a[m - 1][i] + " ");
                }
                m--;
            }
 
            // Print the first column from the remaining
            // columns */
            if (l < n) {
                for (i = m - 1; i >= k; --i) {
                    System.out.print(a[i][l] + " ");
                }
                l++;
            }
        }
    }
 
    // Driver Code
    public static void main(String[] args)
    {
        int R = 3;
        int C = 6;
        int a[][] = { { 1, 2, 3, 4, 5, 6 },
                      { 7, 8, 9, 10, 11, 12 },
                      { 13, 14, 15, 16, 17, 18 } };
        
        // Function Call
          spiralPrint(R, C, a);
    }
}
 
// Contributed by Pramod Kumar