getchar problem

// apple xcode
// paulogp

/* getchar problem */
/* Despite what it says in the brochure, getchar() does not read a
 single char­ acter from the keyboard. That's what the getchar()
 function returns, but it's not what the function does.
 Internally, getchar() reads what's called standard input. It grabs
 the first char­acter you type and stores it, but afterward it sits
 and waits for you to type something that signals "the end." */

#include <stdio.h>

int main (int argc, const char * argv[])
{
    char the_char_a, the_char_b;

    printf("caracter a: ");
    the_char_a = getchar();
    fpurge(stdin); // fflush(stdin);

    printf("caracter b: ");
    the_char_b = getchar();

    printf("a: %c; b: %c\n", the_char_a, the_char_b);

    return 0;
}