isnull

// apple xcode
// paulogp

/* isnull: string nula */
#include <stdio.h>
#include <string.h>

int isnull (char *the_input);

int isnull (char *the_input)
{
    //if (the_input[0] == '\0') // only the first is needed
    if (the_input == NULL) // when using fgets with strtok
        return 1; // null
    else
        return 0;
}

int main (int argc, const char * argv[])
{
    char the_input[20]; // max 20 digits
    char *the_input_ptr;
    int the_result;

    printf ("palavra: ");
    fgets (the_input, sizeof(the_input), stdin);
    // token \n
    // NOTE: the_file_ptr points to the_file_name
    the_input_ptr = strtok (the_input, "\n");

    the_result = isnull (the_input_ptr);
    if (the_result == 1)
        printf ("nulo");
    else
        printf ("nao nulo");

    return 0;
}