Ubuntu-gr Forum

#include <stdio.h>
#include <string.h> // memset()
#include <stdlib.h> // srand(), rand()
#include <time.h>   // time()

#define ALPHABETA "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
#define NUM_ALPHABETA sizeof(ALPHABETA) / sizeof(ALPHABETA[0])

#define NUM_ROWS 10
#define NUM_COLUMNS 10

int main(void)
{
    int row = 0, col = 0;
    char table[NUM_ROWS][NUM_COLUMNS];

    memset(table, '.', sizeof(table)); // init table with dots
    table[0][0] = ALPHABETA[0];

    srand((unsigned) time(NULL));

    for (int i = 1; i < NUM_ALPHABETA - 1; i++) {
        if ((table[row+1][col] != '.' || row == NUM_ROWS-1) && (table[row-1][col] != '.' || row == 0) && \
            (table[row][col+1] != '.' || col == NUM_COLUMNS-1) && (table[row][col-1] != '.' || col == 0)) {
            break;  // terminate if there is no available position
        }

        while (1) {
            int move = rand() % 4;

            if (move == 0 && row > 0 && table[row-1][col] == '.') {
                row--; // UP
                break;
            }
            else if (move == 1 && col < NUM_COLUMNS-1 && table[row][col+1] == '.') {
                col++; // RIGHT
                break;
            }
            else if (move == 2 && row < NUM_ROWS-1 && table[row+1][col] == '.') {
                row++; // DOWN
                break;
            }
            else if (move == 3 && col > 0 && table[row][col-1] == '.') {
                col--; // LEFT
                break;
            }
        }
        table[row][col] = ALPHABETA[i];
    }

    for (row = 0 ; row < NUM_ROWS; row++) {
        for (col = 0; col < NUM_COLUMNS; col++)
            printf("%c ", table[row][col]);
        putchar('\n');
    }

    return 0;
}