3 dimensional array?

Projects Programming
1

While writing some code for a fellow forum member I came across an interesting problem. Is it possible to make a two dimensional array of character strings (effectively a 3d array)? It seems like it should be possible but I don't know and I'm not with my arduino to try it.

Heres what I think it should look like

char* tricks[][] = {
            {"first", "second", "third", "fourth", "fifth", "sixth", "seventh"},
            {"first", "second", "third", "fourth", "fifth", "sixth", "seventh"},
            {"first", "second", "third", "fourth", "fifth", "sixth", "seventh"},  
            {"first", "second", "third", "fourth", "fifth", "sixth", "seventh"}
          };

The reason I want to do it like this is so that I can do a for loop and call a random string from each group (basically)

2

You must provide the size out of the rows at least. Or better provide both sizes for row and column. Note that three dimensions can take quite some memory space.

3

Yeah I tried to compile it and it said I had to tell it how big it was, which I usually do I just forgot. I changed it to char* tricks[4][6] and it gave me the below error, which leads me to believe that its impossible. As for the space I know, but thats pretty much the only thing that requires large amounts of space so I think its safe.

error: too many initializers for 'char* [6]'

I wrote the code a different way but it would be much more elegant to use an array like this one if possible. See this thread:

http://arduino.cc/forum/index.php/topic,70173.0.html

This is why I was wondering...

4

I changed it to char* tricks[4][6] and it gave me the below error, which leads me to believe that its impossible.

Well yes, putting seven initialisers into a six element array is impossible.
Did you mean "char* tricks [4][7] = " ?

5

Wow now I feel dumb haha. I neglected to check how many elements there were when I wrote it...

6

int cube_matrix[3][3][3] = {

{{0,1,2},// row 0
{3,4,5},
{6,7,8}},

{ {9,10,11},
{12,13,14},
{15,16,17}},

{{18,19,20},
{21,22,23},
{24,25,26}}

};

void setup() {
// put your setup code here, to run once:
Serial.begin(9600);
}

void loop() {
// put your main code here, to run repeatedly:
for (int i=0;i<3;i++){
for (int j=0;j<3;j++){
for(int k=0;k<3;k++){

Serial.println(cube_matrix*[j][k]);*

  • delay(1000);*
    }
    }
    }
    }
7

Just supply the column count. Let the compiler count the rows for you

const uint8_t numColumns = 7;

const char * const tricks[][numColumns] = {
  {"first", "second", "third", "fourth", "fifth", "sixth", "seventh"},
  {"first", "second", "third", "fourth", "fifth", "sixth", "seventh"},
  {"first", "second", "third", "fourth", "fifth", "sixth", "seventh"},
  {"first", "second", "third", "fourth", "fifth", "sixth", "seventh"},
};

const uint8_t numRows = sizeof(tricks) / sizeof(tricks[0]);
8

@gfvalvo

You're replying to a nearly 8 year old post :wink:

I think this is the second thread @Gilberto_Gozzi revived. I'm not even sure if this is a question or a solution.

9

Yea, just noticed that.