Using a button to cycle an array

Question

So. I would like to cycle through an array using a button. My current code goes through if statements when the button is pushed. In each if statement I have a loop to print out a list of strings. I am curious if there is anyway to directly cycle through an array using buttons instead of this indirect route I have taken.

Last question - Is there a way to set the indents in the Arduino IDE to make formatting easier here?

//------------------------------------------------------------------------------------------------
// Displays information when a push button is pressed. Also turns on and off a corresponding led.
// 5/3/2016
//------------------------------------------------------------------------------------------------

// declare variables

char* titles[] = {
  "RELATION",
  "FIRST NAME",
  "LAST NAME",
  "LOCATION",
  "PHONE NUMBER"
};
char* user_info[] = {
  "SELF",
  "JOHN",
  "SMITH",
  "FLORIDA",
  "999-888-6666"
};
char* econ_one[] = {
  "BROTHER",
  "MICHAEL",
  "SMITH",
  "FLORIDA",
  "999-888-5555"
};
char* econ_two[] = {
  "WIFE",
  "EMILY",
  "SMITH",
  "FLORIDA",
  "999-888-4444"
};
char* econ_three[] = {
  "SISTER",
  "SOPHIA",
  "ADAMS",
  "NEW YORK",
  "888-777-3333"
};

int ledPinOne = 2;
int ledPinTwo = 3;
int ledPinThree = 4;
int ledPinFour = 5;
int buttonPin = 6;
int state = 0;
// setup - set pins

void setup() {
  Serial.begin(9600);
  pinMode(ledPinOne, OUTPUT);
  pinMode(ledPinTwo, OUTPUT);
  pinMode(ledPinThree, OUTPUT);
  pinMode(ledPinFour, OUTPUT);
  pinMode(buttonPin, INPUT);
  Serial.println("Emergency Contact");
}

// main
void loop() {
  if (digitalRead(buttonPin)) {
    if (state == 0) {
      int x;
      for (x = 0; x <= 4; x++) {
        Serial.println(" ");
        Serial.print(titles[x]);
        Serial.print(" ");
        Serial.print(user_info[x]);
      }
      Serial.println(" ");
      setLights(HIGH, LOW, LOW, LOW);
      state = 1;
    } else if (state == 1) {
      int y;
      for (y = 0; y <= 4; y++) {
        Serial.println(" ");
        Serial.print(titles[y]);
        Serial.print(" ");
        Serial.print(econ_one[y]);
      }
      Serial.println(" ");
      setLights(LOW, HIGH, LOW, LOW);
      state = 2;
    } else if (state == 2) {
      int z;
      for (z = 0; z <= 4; z++) {
        Serial.println(" ");
        Serial.print(titles[z]);
        Serial.print(" ");
        Serial.print(econ_two[z]);
      }
      Serial.println(" ");
      setLights(LOW, LOW, HIGH, LOW);
      state = 3;
    } else if (state == 3) {
      int q;
      for (q = 0; q <= 4; q++) {
        Serial.println(" ");
        Serial.print(titles[q]);
        Serial.print(" ");
        Serial.print(econ_three[q]);
      }
      Serial.println(" ");
      setLights(LOW, LOW, LOW, HIGH);
      state = 0;
    }
    delay(1000);
  }
}

// function to turn LEDs on/off

void setLights(int one, int two, int three, int four) {
  digitalWrite(ledPinOne, one);
  digitalWrite(ledPinTwo, two);
  digitalWrite(ledPinThree, three);
  digitalWrite(ledPinFour, four);
}

output image

https://www.dropbox.com/sc/fwll0qe7cyye1mt/AAD5vI9buU_X0bl04KXFAQyja

Answer 1

I would recommend using multidemnsional arrays for both your contacts and your light states.

//------------------------------------------------ declare variables

char* titles[] = {"RELATION", "FIRST NAME", "LAST NAME", "LOCATION", "PHONE NUMBER"};

char* econs[][5] = {
  {"SELF", "JOHN", "SMITH", "FLORIDA", "999-888-6666"},
  {"BROTHER", "MICHAEL", "SMITH", "FLORIDA", "999-888-5555"},
  {"WIFE", "EMILY", "SMITH", "FLORIDA", "999-888-4444"},
  {"SISTER", "SOPHIA", "ADAMS", "NEW YORK", "888-777-3333"}
};

uint8_t lights[][4] {   {HIGH, LOW, LOW, LOW},
  {LOW, HIGH, LOW, LOW},
  {LOW, LOW, HIGH, LOW},
  {LOW, LOW, LOW, HIGH},
};

int ledPinOne = 2;
int ledPinTwo = 3;
int ledPinThree = 4;
int ledPinFour = 5;
int buttonPin = 6;
int state = 0;

//------------------------------------------------ setup - set pins
void setup() {
  Serial.begin(9600);

  pinMode(ledPinOne, OUTPUT);
  pinMode(ledPinTwo, OUTPUT);
  pinMode(ledPinThree, OUTPUT);
  pinMode(ledPinFour, OUTPUT);
  pinMode(buttonPin, INPUT);

  Serial.println("Emergency Contact");
}

//------------------------------------------------ main
void loop() {


  if (digitalRead(buttonPin))
  {
    if (state > 3)
      state = 0;

    {
      for (int y = 0; y <= 4; y++)
      {
        Serial.println(" ");
        Serial.print(titles[y]);
        Serial.print(" ");
        Serial.print(econs[state][y]);
      }

      Serial.println(" ");
      setLights(lights[state][0], lights[state][1], lights[state][2], lights[state][3]);
    }

    delay(1000);
    state++;

  }

}


//------------------------------------------------ function to turn LEDs on/off

void setLights(int one, int two, int three, int four)
{
  digitalWrite(ledPinOne, one);
  digitalWrite(ledPinTwo, two);
  digitalWrite(ledPinThree, three);
  digitalWrite(ledPinFour, four);
}

I haven't tested the above, but it should provide the same result.

As for the second part of your question, there is an autoformat tool in the Tools menu that will auto-indent your code. Ctrl-T will do the same.

Answer 2

As for your question, your way is (kind of) the best way.

I just saw a problem: when you keep the button pressed you will go on showing. Moreover I really don't like the delay at the end, and if its purpose is just to avoid bounces, well, use the Bounce2 class.

As for the repeated ifs, I prefer a switch-case statement.

I highly suggest you to use the Bounce2 class, though. Here is an example of its usage:

Bounce debouncer = Bounce(); 

void setup()
{
    ...
    pinMode(buttonPin, INPUT);
    debouncer.attach(buttonPin);
    debouncer.interval(5); // interval in ms
}

void loop()
{
    debouncer.update();
    if (debouncer.rose())
    {
        switch (state)
        {
        case 0:
            {
                int x;
                for (x=0; x <= 4; x++)
                {
                    Serial.println(" ");
                    Serial.print(titles[x]);
                    Serial.print(" ");
                    Serial.print(user_info[x]);
                }
                Serial.println(" ");
                setLights(HIGH, LOW, LOW, LOW);
                state = 1;
            }
            break;
        case 1:
        ...
        }
    }
}

As you can see the class has a rose member, which tells you if the button was just pressed (only on the rising edge).

Now, your particular problem can be solved in another way. Since you are repeating the same code for all the cases, you can cycle through two arrays; one stating which is the second array you need to use, the other the lights.

This is an example. Please note that I haven't tested it, so there might be some errors

char ** second_array[] = { user_info, econ_one, econ_two, econ_three }
uint8_t lights[][4] {   {HIGH, LOW, LOW, LOW},
                        {LOW, HIGH, LOW, LOW},
                        {LOW, LOW, HIGH, LOW},
                        {LOW, LOW, LOW, HIGH},
                    }

void loop()
{
    debouncer.update();
    if (debouncer.rose())
    {
        int x;
        for (x=0; x <= 4; x++)
        {
            Serial.println(" ");
            Serial.print(titles[x]);
            Serial.print(" ");
            Serial.print(second_array[state][x]);
        }
        Serial.println(" ");
        setLights(lights[state][0], lights[state][1], lights[state][2], lights[state][3]);
        state++;
        if (state >= 4)
            state = 0;
    }
}

Try to use it and then report back if there is some issue ;)