i am writing a simple code by using ref keyword. As i understand struct can be really slow on copying things. In order to make it faster you should use ref. So i wrote this simple code below.
using System;
namespace ConsoleApplication4
{
    class Program
    {
        public static void returns(ref s s1)
        {
            for (int i = 0; i < 100;i++)
            {
                s1.z += i;
            }
        }
        static void Main(string[] args)
        {
            s s1 = new s();
            returns(ref s1);
        }
    }
}
it gave me the error "Error 1 Inconsistent accessibility: parameter type 'ref is less accessible than method". I checked one of stackoverflow question. Using ref seemed like that. What is my mistake here. Can you give me any advice.
Thanks in advance.
 
     
    