//Create an array of pointers and initialize 4 different strings.  These strings are programmed
// into flash during programming because the 'const' keyword is used to make the pointers point
// to flash memory.  Also, create some generic variables used for the loops.
const char *p[4] = {"ALARM", "FAULT", "SENSOR", "UNLOCK"};
const char **pp = &p[0];
char y;


//Function prototype
void string_access(const char **message_pointer);

void setup() {
  Serial.begin(115200);
  //Step through the following code and watch the 'y' variable.  This code will separately access each
  // string in the array.  This code will pass the pointer address to the strings to the function.  It will
  // increment the double pointer to point to the next string.  This method demonstrates how to pass the
  // pointer to the function.

  //Access "ALARM"
  pp = &p[0];
  string_access(&*pp);

  //Access "FAULT"
  pp++;
  string_access(&*pp);

  //Access "SENSOR"
  pp++;
  string_access(&*pp);

  //Access "UNLOCK"
  pp++;
  string_access(&*pp);

}

void loop() {
  // put your main code here, to run repeatedly:

}


//This function receives the address of the array pointer to the text strings.  The
// double pointer allows us to pass the address of pointers to functions.  The function
// will access each character in the string until the NULL character is reached.
void string_access(const char **message_pointer)
{
  char i;

  i = 0;
  do {
    y = *(*message_pointer + i);
    i++;
    Serial.print(y);
  } while (y != '\0');
  Serial.println();
}