In C++, how do I write a 3-dimensional array?

Question

Thanks for looking!

Background

I am building a quadcopter and am placing on each of it's four arms a strip of RGB LEDs which are individually addressable. There are 6 LEDs per strip.

Further, there are six steps in a sequence to how I wish to toggle the lights so all six lights on the strip don't necessarily toggle at once.

In pseudo code, here is what I am trying to create:

someArray = A group of 4 LED strips {Strip 1: [
    Step 1: [ LED 1: [R, G, B], . . ., LED 6: [R, G, B] ],
    . . .,
    Step 6: [ LED 1: [R, G, B], . . ., LED 6: [R, G, B] ],
],
. . .,
Strip 4: [
    Step 1: [ LED 1: [R, G, B], . . ., LED 6: [R, G, B] ],
    . . .,
    Step 6: [ LED 1: [R, G, B], . . ., LED 6: [R, G, B] ],
]};

I am using an Arduino to drive the lights, and the code is in C++ with which I am not very familiar.

What I have tried so far:

Here is the code I have tried so far, but when I compile in the Arduino IDE, I get an error that says "Braces around scalar initializer for type 'int'".

int gpsHoldArr[4][6][6] = {
  {
    {{255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}}
},
  {
    {{255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}}
},
  {
    {{255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}}
},
  {
    {{255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}}
},
};

What am I missing here?

Intended Usage

Intended use would be something like this:

//iterate each of the 6 sets of RGB values and assign them to the correct (sequential) LED
void toggleLights(int lights[]){
  for(int i = 0; i <= 6; ++i) 
  {
    set_color_led(i, lights[i][0], lights[i][1], lights[i][2]);
  } 
}

toggleLights(gpsHoldArr[1][0]);//Get the first step of the second arm.

Thanks in advance.

Pubby · Accepted Answer · 2013-01-19 06:33:30Z

You wrote the initialization for a 4d array as RGB has 3 components. You probably want to do something like this:

struct rgb {
  int r, g, b;
};

rgb gpsHoldArr[4][6][6] = {
  {
    {{255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}}
},
  {
    {{255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}}
},
  {
    {{255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}}
},
  {
    {{255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {0,0,0}},
    {{255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}, {255,0,0}}
},
};

Or, change your declaration to this:

int gpsHoldArr[4][6][6][3]

jdr5ca · Accepted Answer · 2013-01-19 06:47:47Z

3

Use a byte and cut the memory usage in half

typedef struct rgb_t {
  byte r;
  byte g;
  byte b;
};

rgb_t gpsHoldArr[4][6][6] = {

answered Jan 19, 2013 at 6:47

jdr5ca

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