Verificacao do BI PT

// apple xcode
// paulogp
/* BI check */
#include <stdio.h>

#define MAX_VECT_LENGTH 50

int vector_size (char *the_vector);
char check_bi (char *the_vector);

int vector_size (char *the_vector)
{
    int i;

    for (i = 0; the_vector[i] != '\0'; i++);

    return (i - 1);
}

char check_bi (char the_vector[])
{
    unsigned long the_vector_size = 0;
    unsigned long the_temp = -1; // avoid empty
    unsigned long the_num = 0;
    int i;

    // vector size
    the_vector_size = vector_size(the_vector);

    // calculus; bi: 8 - 9 digits (including control digit)
    // NOTE: if control digit is 0 is could represent 0 or 10!
    // Exception (0 or 10) not implemented
    if ((the_vector_size == 8) || (the_vector_size == 9))
    {
        for (i = 0; i < the_vector_size; i++)
        {
            // char2num
            the_temp = the_vector[i] - '0';
            // 9a + 8b + 7c + 6d + 5e + 4f + 3g + 2h + 1i
            the_num = (the_temp * (the_vector_size - i)) + the_num;
        }

        // final
        the_temp = the_num % 11;
        if (the_temp == 0)
            return 1; // valido
        else
            return -1; // invalido
    }
    else
    {
        return 0;
    }
}

int main (int argc, const char * argv[])
{
    char the_vector[MAX_VECT_LENGTH];
    int the_status = 0;

    // get number
    printf("bi (incl digito de controlo): ");
    fgets(the_vector, MAX_VECT_LENGTH, stdin);

    // calculus
    the_status = check_bi(the_vector);

    switch(the_status)
    {
        case 1:
            printf("numero de BI valido\n");
            break;
        case -1:
            printf("numero de BI invalido\n");
            break;
        default:
            printf("numero de digitos BI invalido para verificacao\n");
    }

    return (0);
}