Use of array in case statement

Question

I want to know how I can use case statement for each array.

Below is my code:

int incomingByte = 0;
void setup()
{
 Serial.begin(115200);
 for (int thisPin = 2; thisPin < 6; thisPin++)
 {
 pinMode(thisPin, OUTPUT);
 }
}
void loop()
{
 int button1[] = {0xFF, 0x04, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x05};
 int button2[] = {0xFF, 0x04, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x06};
 int button3[] = {0xFF, 0x04, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08};
 int button4[] = {0xFF, 0x04, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x0C};
 if (Serial.available() > 0)
 {
 incomingByte = Serial.read();
 }
 switch (incomingByte)
 {
 case button1:
 digitalWrite(2, HIGH);
 break;
 case button2:
 digitalWrite(3, HIGH);
 break;
 case button3:
 digitalWrite(4, HIGH);
 break;
 case button4:
 digitalWrite(5, HIGH);
 break;
 default:
 for (int thisPin = 2; thisPin < 6; thisPin++)
 {
 digitalWrite(thisPin, LOW);
 }
 }
} 

Answer 1

Not checked/compiled, just to give an idea.

/* One button message is 12 bytes, it is assumed that all received messages are 12 bytes. If note, you have to check later differently. */
#define MSG_SIZE 11 
byte incomingBytes[MSG_SIZE]; /* Storage for 11 bytes */
byte index = 0; /* Current byte to set within incomingBytes */
void setup()
{
 Serial.begin(115200);
 for (int thisPin = 2; thisPin < 6; thisPin++)
 {
 pinMode(thisPin, OUTPUT);
 }
}
void loop()
{
 if (Serial.available() > 0)
 {
 /* Store the next incoming byte. Assume 0xFF is the start of a message. */
 byte incoming_byte = Serial.read();
 if (incoming_byte == 0xFF)
 {
 index = 0;
 }
 incomingBytes[index] = incoming_byte;
 index++;
 if (index >= MSG_SIZE)
 {
 check_message();
 index = 0;
 }
 }
}
/* Checks which button is pressed and performs an action based on the 
pressed button. */
void check_message()
{
 case check_button_pressed())
 {
 case 1:
 digitalWrite(2, HIGH);
 break;
 case 2:
 digitalWrite(3, HIGH);
 break;
 case 3:
 digitalWrite(4, HIGH);
 break;
 case 4:
 digitalWrite(5, HIGH);
 break;
 default:
 for (int thisPin = 2; thisPin < 6; thisPin++)
 {
 digitalWrite(thisPin, LOW);
 }
 }
} 
/* Checks which button is pressed by comparing 11 incoming bytes to the
four buttons to be checked. Returns -1 for an illegal message/unsupported
button and 1, 2, 3 or 4 for the pressed button. */
int check_button_pressed()
{
 int button_pressed = -1;
 if ((incomingBytes[0] == 0xFF) &&
 (incomingBytes[1] == 0x04) &&
 (incomingBytes[3] == 0x00) &&
 (incomingBytes[4] == 0x00) &&
 (incomingBytes[5] == 0x00) &&
 (incomingBytes[6] == 0x00) &&
 (incomingBytes[7] == 0x00) &&
 (incomingBytes[8] == 0x00) &&
 (incomingBytes[9] == 0x00))
 {
 if ((incomingBytes[2] == 0x01) && (incomingBytes[10] == 0x05))
 {
 button_pressed = 1;
 }
 else if ((incomingBytes[2] == 0x02) && (incomingBytes[10] == 0x06))
 {
 button_pressed = 2;
 }
 else if ((incomingBytes[2] == 0x04) && (incomingBytes[10] == 0x08))
 {
 button_pressed = 3;
 }
 else if ((incomingBytes[2] == 0x08) && (incomingBytes[10] == 0x0C))
 {
 button_pressed = 4;
 }
 }
 return button_pressed;
}

• Russell Borogove: I'd add something to explicitly re-sync the stream when 0xFF is received, to handle variable length messages and cases where the serial connection is established in mid-message, but otherwise this is a good approach.
• Michel Keijzers: True, this is in case all messages are same length. But I don't know what the start of a message is, probably 0xFF. If so, if character is encounter, set Index to 0
• Michel Keijzers: @RussellBorogove I adapted the code for it.
• Michel Keijzers: yw ... if it is helpful, you can upvote the helpful answers, and select one which you consider best to answer your question (and press accept).

Answer 2

case doesn't work like that; it can only switch on a single integer. Are you trying to pattern-match those sequences of bytes? You'll have to use some sort of state machine instead, keeping track of what bytes you've received and where in the expected pattern you are.

• Ali khan: Can you give me some hints? I am a newbie and i don't know much about Arduino. Thanks
• user29840: As mentioned it won't work. But also note you read a single byte, but your arrays have eleven items in them. You should probably read 11 bytes and use a comparison routine. (memcmp, etc.)