Possible to assign the Length of an array through a function with parameters?

Question

I'm having about 4 int arrays that need their length calculated, assigned to them and then populated. I was trying to thin out the code by using a function with parameters, instead of repeating long calculations 4 times, but I can't seem to set the length by designating the array as a parameter. I tried something like the code below:

for(int i=0; i<4; i++)
if(i==0) SetLength(array1);
else if(i==1) SetLength(array2);
else if(i==2) SetLength(array3);                   
else if(i==3) SetLength(array4);      

SetLength(int[] array)
{
    //calculations for length here
    //int result=...;

    array = new int[result];

    //getting info for populating the array
    for(int i=0; i<result; i++)
    array[i]=some_value[i];
}            

Most of the code seems to work, except for the length assigning part. Any ideas?

Answer 1

Why not use a collection class List or ArrayList which has .Add methods

Answer 2

If you need to reallocate the array within method and want it to update the variable you've passed as method parameter you have to make the parameter ref or out:

SetLength(ref int[] array)

for(int i=0; i<4; i++)
if(i==0) SetLength(ref array1);
else if(i==1) SetLength(ref array2);
else if(i==2) SetLength(ref array3);                   
else if(i==3) SetLength(ref array4); 

Answer 3

You can do it without ref modifier as MarcinJuraszek suggests like this

for(int i=0; i<4; i++)
if(i==0) array1 = SetLength();
else if(i==1) array2 = SetLength();
else if(i==2) array3 = SetLength();                   
else if(i==3) array4 = SetLength();      

int[] SetLength()
{
    //calculations for length here
    //int result=...;

    var array = new int[result];

    //getting info for populating the array
    for(int i=0; i < result; i++)
       array[i] = some_value[i];

    return array;
} 

And by the way, you don't really need a cycle here. For your original code

SetLength(array1);
SetLength(array2);
SetLength(array3);                   
SetLength(array4); 

would suffice.