action and func delegate

Action is a delegate (pointer) to a method, that takes zero, one or more input parameters, but does not return anything.
Func is a delegate (pointer) to a method, that takes zero, one or more input parameters, and returns a value.

Example for Action and Func:

class Program
{
    static void Main(string[] args)
    {
        Action<int,int> testAction = new Action<int,int>(Add);
        testAction.Invoke(123,234);           

        Func<int,int, double> testFunc = new Func<int,int, double>(Multiply);
        Console.WriteLine(testFunc(5,6));   
    }

    static void Add(int i,int j)
    {
        Console.WriteLine(i+j);
    }

    static double Multiply(int i,int j)
    {
        return (double)i*j;
    }
}