Question

Hey I need a little help with unsigned char bit access. I need to test to ensure that “channel” which is an unsigned char (UCHAR) is 6 digits long (i have that) and that the the number enter is infact a binary number (aka 1s or 0s). I at a loss for how to access it. Any help would be great!

void binEnter(void *channel){
int i;
for (i=0; i<6; i++) {
redo:
    printf("Enter binary value for Channel %d: ",i);
    scanf("%s",(UCHAR *)channel);
    if (strlen(channel)!=6) {
        printf("Error entry must be six digits!\n");
        goto redo;
    }
}
}

Answer 1

Make a loop to check each digit.

char *string = channel;
for (j = 0; j < 6; j++)
{
  if ((string[j] != '0') && (string[j] != '1'))
  {
    // error
  }
}

You could also just use strtol(3) and check the result in endptr to see if you got a 6-digit number.