c# Treat an array like pointer

Question

I am trying to implement a merge-sort in c# to try and learn the language. I am having trouble splitting the array in the divide step. I come from a c background and would do something like this:

void MergeSort(int array[], int size)
{
    if (size == 1) 
        return;
    MergeSort(array, size/2);
    MergeSort(array + size/2, size - size/2);
}

My question is, can you do something similar in c#? I am aware there is take and skip methods, but is this the best way?

Several things - you can use List<int> instead of the array (it is a class, so the reference is what gets passed, by value). And though you can use pointers with unsafe, that's not really the C# way. — Oded
– Oded, Commented Mar 24, 2013 at 12:08
My point was more that for resizing it is more appropriate. Arrays are not used as often as other collection types in C#. Arrays are reference types. — Oded
– Oded, Commented Mar 24, 2013 at 12:14
using pointers is possible in c#, but it is one of the more advaned features of the language. if you start learning, you should use the direct addressing — user287107
– user287107, Commented Mar 24, 2013 at 12:15

antonijn · Accepted Answer · 2013-03-24 12:11:19Z

9

Use indexes instead of pointers.

void MergeSort(int[] array, int startIndex, int endIndex){
...
}

edited Mar 24, 2013 at 12:11

antonijn

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answered Mar 24, 2013 at 12:09

alex

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antonijn · Accepted Answer · 2013-03-24 12:20:05Z

2

Perhaps you could pass the index you want to use to the function:

private static void MergeSort(int[] array, int size, int index) {
    if (size == 1) {
        return;
    }
    MergeSort(array, size / 2, index);
    MergeSort(array, size - size / 2, index + size / 2);
}

edited Mar 24, 2013 at 12:20

answered Mar 24, 2013 at 12:10

antonijn

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