#include <stdio.h>
#include <stdbool.h>
#include <time.h>
#include <stdlib.h>

#define ARRAY_COLUMNS   10
#define ARRAY_ROWS      10
#define CHAR_ARRAY      ((int) (sizeof(alphabet) / sizeof(alphabet[0])))

int main(void)
{
    int walking_array[ARRAY_COLUMNS][ARRAY_ROWS], i, j, counter = 0,
        counter2 = 0, new_direction;
    const char alphabet[] = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
                            'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
                            'Q', 'R', 'S', 'T', 'U', 'V', 'X', 'Y',
                            'W', 'Z'};

    // initialize random number generator
    srand( (unsigned) time(NULL) );

    // fill walking_array with dots
    for (i = 0; i < ARRAY_COLUMNS; i++)
    {
        for (j = 0; j < ARRAY_ROWS; j++)
        {
            walking_array[i][j] = '.';
        }
    }

    while (counter < CHAR_ARRAY)
    {
        // to pick random move, take modulus of rand() and 4
        new_direction = rand() % 4;

        if (new_direction == 0)
        {
            if (counter == 1)
            {
                continue;
            }
            else if (walking_array[(counter - 1)][counter2] == '.')
            {
                counter++;
                counter2--;
                walking_array[counter][counter2] = alphabet[counter];
            }
        }

        if (new_direction == 1)
        {
            if (counter > 8)
            {
                continue;
            }
            else
            {
                counter++;
                counter2++;
                walking_array[counter][counter2] = alphabet[counter];
            }
        }

        if (new_direction == 2)
        {
            if (counter2 == 0)
            {
                continue;
            }
            else if (walking_array[counter][(counter2 + 1)] == '.')
            {
                counter++;
                counter2--;
                walking_array[counter][counter2] = alphabet[counter];
            }
        }

        if (new_direction == 3)
        {
            if (counter2 > 8)
            {
                continue;
            }
            if (walking_array[counter][(counter2 + 1)] == '.')
            {
                counter++;
                counter2++;
                walking_array[counter][counter2] = alphabet[counter];
            }
        }
    }

    for (i = 0; i < ARRAY_COLUMNS; i++)
    {
        for (j = 0; j < ARRAY_ROWS; j++)
        {
            printf(" %c", walking_array[i][j]);
        }
        printf("\n");
    }

    return 0;
 }