Multidimensional arrays From C to Swift

Question

In CI have the following multidimensional array:

unsigned wins[8][3] = {{0,1,2},{3,4,5},{6,7,8},{0,3,6},{1,4,7},{2,5,8},{0,4,8},{2,4,6}};

To access the elements I use the following code:

int i;
for(i = 0; i < 8; ++i)     {
    unsigned *positions;
    positions = wins[i];

    unsigned pos0 = positions[0];
    unsigned pos1 = positions[1];
    unsigned pos2 = positions[2];

    if(arrayPassedIn[pos0] != 0 && arrayPassedIn[pos0] == arrayPassedIn[pos1] && arrayPassedIn[pos0] == arrayPassedIn[pos2])
    {
         // Do Something Here
    }

I know in swift I can do something like:

var array = Array<Array<Int>>()

But I'm not sure if this produces the same result for accessing the elements.

Answer 1

You can create a multi-dimentsional array in a pretty similar manner to your C code:

var wins = [[0,1,2],[3,4,5],[6,7,8],[0,3,6],[1,4,7],[2,5,8],[0,4,8],[2,4,6]]

The Swift code to use it the same way as your C code is also pretty similar; the main difference is using a for-in loop instead of the standard for loop (although you could do that too).

for positions in wins {
    var pos0 = positions[0]
    var pos1 = positions[1]
    var pos2 = positions[2]

    if(arrayPassedIn[pos0] != 0 && arrayPassedIn[pos0] == arrayPassedIn[pos1] && arrayPassedIn[pos0] == arrayPassedIn[pos2])
    {
        // Do Something Here
    }
}

Do note that, even though there are similarities, Arrays in Swift are not like arrays in C. For instance, when you're looping over wins , you're actually creating copies of the positions arrays (the actual memory copy only happens if you write to the array, so there's not really a performance penalty). If you then set, say, positions[0] to a different value, that value would not be updated in wins like it would if this were C.

Answer 2

I have never worked in obj-C, but in swift I think the equivalent is:

let array: [(Int, Int, Int)] = [(0,1,2),(3,4,5),(6,7,8),(0,3,6),(1,4,7),(2,5,8),(0,4,8),(2,4,6)]
println(array[2].0) //6