Question

I have a list of integers List<int> in my C# program. However, I know the number of items I have in my list only at runtime.

Let us say, for the sake of simplicity, my list is {1, 2, 3}
Now I need to generate all possible combinations as follows.

{1, 2, 3}
{1, 2}
{1, 3}
{2, 3}
{1}
{2}
{3}

Can somebody please help with this?

Answer 1

try this:

static void Main(string[] args)
{

    GetCombination(new List<int> { 1, 2, 3 });
}

static void GetCombination(List<int> list)
{
    double count = Math.Pow(2, list.Count);
    for (int i = 1; i <= count - 1; i++)
    {
        string str = Convert.ToString(i, 2).PadLeft(list.Count, '0');
        for (int j = 0; j < str.Length; j++)
        {
            if (str[j] == '1')
            {
                Console.Write(list[j]);
            }
        }
        Console.WriteLine();
    }
}