Miscellany

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

#define SIZE_X 25
#define SIZE_Y 25

unsigned max_horizontal(unsigned **matrix, int size_x, int size_y)
{
    int i, j, k, l;
    unsigned product, *mat[size_y];
    unsigned max = 0;

	for (l = 0 ; l < size_x ; l++)
                mat[l] = (unsigned *)matrix + size_y*l;

     for (i = 0; i < size_x; ++i) {
        for (j = 0; j < size_y - 4; ++j) {
            product = 1;
            for (k = j; k < j + 5; ++k) {
                product *= mat[i][k];
            }

            if (product > max) {
                max = product;
            }
        }
    }

    return max;
}

int main(void)
{
    unsigned matrix[SIZE_X][SIZE_Y] = {
        { 8,  2, 22, 97, 38, 15,  0, 40,  0, 75,  4,  5,  7, 78, 52, 12, 50, 77, 91,  8, 49, 49, 99, 40, 17},
        {81, 18, 57, 60, 87, 17, 40, 98, 43, 69, 48,  4, 56, 62,  0, 81, 49, 31, 73, 55, 79, 14, 29, 93, 71},
        {40, 67, 53, 88, 30,  3, 49, 13, 36, 65, 52, 70, 95, 23,  4, 60, 11, 42, 69, 24, 68, 56,  1, 32, 56},
        {71, 37,  2, 36, 91, 22, 31, 16, 71, 51, 67, 63, 89, 41, 92, 36, 54, 22, 40, 40, 28, 66, 33, 13, 80},
        {24, 47, 32, 60, 99,  3, 45,  2, 44, 75, 33, 53, 78, 36, 84, 20, 35, 17, 12, 50, 32, 98, 81, 28, 64},
        {23, 67, 10, 26, 38, 40, 67, 59, 54, 70, 66, 18, 38, 64, 70, 67, 26, 20, 68,  2, 62, 12, 20, 95, 63},
        {94, 39, 63,  8, 40, 91, 66, 49, 94, 21, 24, 55, 58,  5, 66, 73, 99, 26, 97, 17, 78, 78, 96, 83, 14},
        {88, 34, 89, 63, 72, 21, 36, 23,  9, 75,  0, 76, 44, 20, 45, 35, 14,  0, 61, 33, 97, 34, 31, 33, 95},
        {78, 17, 53, 28, 22, 75, 31, 67, 15, 94,  3, 80,  4, 62, 16, 14,  9, 53, 56, 92, 16, 39,  5, 42, 96},
        {35, 31, 47, 55, 58, 88, 24,  0, 17, 54, 24, 36, 29, 85, 57, 86, 56,  0, 48, 35, 71, 89,  7,  5, 44},
        {44, 37, 44, 60, 21, 58, 51, 54, 17, 58, 19, 80, 81, 68,  5, 94, 47, 69, 28, 73, 92, 13, 86, 52, 17},
        {77,  4, 89, 55, 40,  4, 52,  8, 83, 97, 35, 99, 16,  7, 97, 57, 32, 16, 26, 26, 79, 33, 27, 98, 66},
        {88, 36, 68, 87, 57, 62, 20, 72,  3, 46, 33, 67, 46, 55, 12, 32, 63, 93, 53, 69,  4, 42, 16, 73, 38},
        {25, 39, 11, 24, 94, 72, 18,  8, 46, 29, 32, 40, 62, 76, 36, 20, 69, 36, 41, 72, 30, 23, 88, 34, 62},
        {99, 69, 82, 67, 59, 85, 74,  4, 36, 16, 20, 73, 35, 29, 78, 31, 90,  1, 74, 31, 49, 71, 48, 86, 81},
        {16, 23, 57,  5, 54,  1, 70, 54, 71, 83, 51, 54, 69, 16, 92, 33, 48, 61, 43, 52,  1, 89, 19, 67, 48}
    };
    /*unsigned max = 0;*/
    /*unsigned i;*/

    printf("%u\n", max_horizontal((unsigned **)matrix, SIZE_X, SIZE_Y));

    return EXIT_SUCCESS;
}