C#

OriginalGriff wrote:

structs are imutable, classes are not

static void Main(string[] args)
{
    List<int> items = new List<int>(new int[] { 1, 2, 3, 4, 5, 1, 2, 3, 4 });

    List<int> nextIndices = new List<int>();
    try
    {
        for (int i = 0; i < items.Count() - 1; i++)
        {

            nextIndices.Add(FindIndexAfter(items, i, toMatch => toMatch == items[i]));
        }
    }
    catch (Exception ex)
    {
        Console.WriteLine(ex);
    }

    for (int j = 0; j < nextIndices.Count(); j++)
    {
        Console.WriteLine(nextIndices[j]);
    }

    Console.WriteLine("Program complete...");
    Console.ReadKey();
}

static int FindIndexAfter<T>(List<T> items, int startIndex, Func<T, bool> predicate)
{
    if (startIndex < 0)
        throw new ArgumentOutOfRangeException("startIndex",
                     "Start index cannot be negative.");
    if (startIndex >= items.Count())
        throw new ArgumentOutOfRangeException("startIndex",
                     "Start index must be less than the number of items");
    startIndex++;
    while (startIndex < items.Count())
    {
        if (predicate(items[startIndex]))
            return startIndex;
        startIndex++;
    }

    return -1;
}

5
6
7
8
-1
-1
-1
-1
Program Complete

1
3
5
7
Program Complete

int i = 1;
int j = i;
j++;
Console.WriteLine(i);

Calla wrote:

Use a struct if you have no need for methods or to use inheritance and you only need a structure to store data

OriginalGriff wrote:

Sounds like you can't use methods to me!