Passing subarrays as parameter

Carl

Dear community,

How do I pass a subarray from a multidimensional array as a parameter to a function?

In c the code would be like:
int array[5][5];
array[3][1]= 3;
dosomething(array[3]); // passes the 4th subarray to the function

Declared as:
void dosomething(int[]);

How will the port to c# look like?

int[][] array= new array[5][5]; // syntax error
int[][] array= new array[5,5]; // compile error: cannot cast [,] implicitely to [][]
int[,] array= new array[5,5];
array[3][1]= 3;
dosomething(array[3]); // compile error, 2 dimensions expected

Can someone help me out?

Thanks,
Carl

2 Replies

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Alan19y ago
One thing I should perhaps have mentioned in my previous reply is that you can also declare multidimensional arrays in C#. These differ from 'jagged' arrays in that the array elements do have of be of the same length and they are therefore more akin to multidimensional arrays in C which also have to be rectangular. Confusingly, though, the syntax is different. Worse still, there is (AFAIK) no easy way to obtain a subarray - you have to build them up manually.

Anyway, the previous code using a multidimensional array would look like this:

int[,] array = new int[5,5]; // all values set to zero
array[3,1] = 3;
int[] array3 = new int[5]; // declare one dimensional array to get subarray in 4th row
for(int i = 0; i < 5; i++)
array3[i] = array[3, i];
dosomething(array3);
Alan19y ago
Because the array elements in a 'jagged' array don't necessarily have to be the same length, you have to do something like this:

int[][] array= new int[5][];
for (int i = 0; i < 5; i++)
array[i] = new int[5];
array[3][1]= 3;
dosomething(array[3]);