Print a given matrix in spiral form

#include <stdio.h>

#define R 3

#define C 6

void spiralPrint(int m, int n, int a[R][C])

{

    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)

        {

            printf("%d ", a[k][i]);

        }

        k++;

        /* Print the last column from the remaining columns */

        for (i = k; i < m; ++i)

        {

            printf("%d ", a[i][n-1]);

        }

        n--;

        /* Print the last row from the remaining rows */

        if ( k < m)

        {

            for (i = n-1; i >= l; --i)

            {

                printf("%d ", a[m-1][i]);

            }

            m--;

        }

        /* Print the first column from the remaining columns */

        if (l < n)

        {

            for (i = m-1; i >= k; --i)

            {

                printf("%d ", a[i][l]);

            }

            l++;   

        }       

    }

}

/* Driver program to test above functions */

int main()

{

    int a[R][C] = { {1,  2,  3,  4,  5,  6},

        {7,  8,  9,  10, 11, 12},

        {13, 14, 15, 16, 17, 18}

    };

    spiralPrint(R, C, a);

    return 0;

}