three dimensional array in c#

Question

I am translating an old VC++ code to C#. In the C++ program, I have a three dimensional array, with the third dimension specified at run-time,

int * init_ltr [26][28];

int init_ltr_size = x;      // gets assigned to something

// array allocated and initialized
for (i=0; i < 26; i++)
    for (j=0; j < 28; j++)
        init_ltr[i][j] = new int [init_ltr_size];

I can then reference items later like:

init_ltr[firstchar-'a'][secchar-'a'][ix] = wordnum;

How do I do this in C#? I tried declaring it as int [] init_ltr [26][28] but the compiler didn't like that. If possible, I would like to retain a three-dimensional array (instead of using lists or something else) so I don't have to go and change tons of my code.

"...instead of using lists ..." - You do realise that List with its Item property allows for [ ] shorthand so no code change is required — user585968
– user585968, Commented May 1, 2017 at 4:15
Anyway, your problem isn't "dynamic" so you don't need "lists" — user585968
– user585968, Commented May 1, 2017 at 6:35

Roy Sanchez · Accepted Answer · 2017-05-01 04:22:18Z

1

In c# you have two options, jagged arrays and multidimensional arrays. Multidimensional arrays tend to have better syntax, see below:

Jagged array:

int[][][] init_ltr = new int[26][][];

int init_ltr_size = x;

// array allocated and initialized
for (i=0; i < 26; i++)
    init_ltr[i] = new int[28][];
    for (j=0; j < 28; j++)
        init_ltr[i][j] = new int[init_ltr_size];

init_ltr[0][0][0] = 0;

Multidimensional array:

int[,,] init_ltr = new int[26, 28, x];
init_ltr[0,0,0] = 0;

answered May 1, 2017 at 4:22

Roy Sanchez

8546 silver badges14 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

tcrosley Over a year ago

Thanks, the jagged array solution is closest to what I was trying to do.

DesertFox · Accepted Answer · 2017-05-01 04:19:11Z

1

C#

    var size1 = 26;
    var size2 = 28;

    var initLtr = new int[size1][][];
    var initLtrSize = 33;      // gets assigned to something

    for (var i = 0; i < size1; i++)
    {
        initLtr[i] = new int[size2][];
        for (var j = 0; j < size2; j++)
            initLtr[i][j] = new int[initLtrSize]; //it could even be different sizes in each array e.g: new int[i + j]
    }

    initLtr[0][0][0] = 3;

It's just a matter or initialising each of the arrays inside the jagged array.

answered May 1, 2017 at 4:19

DesertFox

8181 gold badge5 silver badges6 bronze badges

Comments

Han · Accepted Answer · 2017-05-01 04:37:59Z

An alternative to the solution posted by DesertFox. Since the first 2 dimensions are hardcoded, you can use 2D array and use jagged array for the 3rd dimension. I use [3, 5] for example. You can change it to [26, 28].

int[,][] init_ltr = new int[3, 5][]; // init_ltr [26, 28][]
int init_ltr_size = 2; // Assign some value
for (var i = 0; i <= init_ltr.GetUpperBound(0); i++)
    for (var j = 0; j <= init_ltr.GetUpperBound(1); j++)
    {
        init_ltr[i, j] = new int[init_ltr_size];
        for (var k = 0; k < init_ltr[i, j].Length; k++)
            init_ltr[i, j][k] = (i + 1) * (j + 1) * (k + 1); // Assign some value
    }

// Print values of arrays. Use int_ltr[i, j][k]
for (var i = 0; i <= init_ltr.GetUpperBound(0); i++)
    for (var j = 0; j <= init_ltr.GetUpperBound(1); j++)
        for (var k = 0; k < init_ltr[i, j].Length ; k++)
            Console.WriteLine(init_ltr[i, j][k]);

Collectives™ on Stack Overflow

three dimensional array in c#

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related