C# error: "An object reference is required for the non-static field, method, or property"

Question

I have two classes, one for defining the algorithm parameters and another to implement the algorithm:

Class 1 (algorithm parameters):

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace VM_Placement
{
    public static class AlgorithmParameters
    {
        public static int pop_size = 100;
        public static double crossover_rate = 0.7;
        public static double mutation_rate = 0.001;

        public static int chromo_length = 300;
        public static int gene_length = 4;
        public static int max_allowable_generations = 400;

        static Random rand = new Random();
        public static double random_num = rand.NextDouble();
    }
}

Class 2 (implement algorithm):

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace VM_Placement
{
    public class Program
    {
        public struct chromo_typ
        {
            public string   bits;
            public float    fitness;

            //public chromo_typ(){
            // bits = "";
            // fitness = 0.0f;
            //}
            chromo_typ(string bts, float ftns)
            {
                bits = bts;
                fitness = ftns;
            }
        };

        public static int GetRandomSeed()
        {
            byte[] bytes = new byte[4];
            System.Security.Cryptography.RNGCryptoServiceProvider rng =
              new System.Security.Cryptography.RNGCryptoServiceProvider();
            rng.GetBytes(bytes);
            return BitConverter.ToInt32(bytes, 0);
        }

        public string GetRandomBits()
        {
            string bits="";

            for (int i = 0; i < VM_Placement.AlgorithmParameters.chromo_length; i++)
            {
                if (VM_Placement.AlgorithmParameters.random_num > 0.5f)
                    bits += "1";
                else
                    bits += "0";
            }
            return bits;
        }

        public static void Main(string[] args)
        {
            Random rnd = new Random(GetRandomSeed());

            while (true)
            {
                chromo_typ[] Population = new chromo_typ[VM_Placement.AlgorithmParameters.pop_size];
                double Target;

                Console.WriteLine("
 Input a target number");
                Target = Convert.ToDouble(Console.ReadLine());

                for (int i = 0; i < VM_Placement.AlgorithmParameters.pop_size; i++)
                {
                    Population[i].bits = GetRandomBits();
                    Population[i].fitness = 0.0f;
                }
            }
        }
    }
}

I am getting an error on Population[i].bits = GetRandomBits(); in Main().

Error is:

An object reference is required for the non-static field, method, or property 'VM_Placement.Program.GetRandomBits()'

Am I missing anything?

question from:https://stackoverflow.com/questions/10264308/c-sharp-error-an-object-reference-is-required-for-the-non-static-field-method

Answer 1

The Main method is Static. You can not invoke a non-static method from a static method.

GetRandomBits()

is not a static method. Either you have to create an instance of Program

Program p = new Program();
p.GetRandomBits();

or make

GetRandomBits() static.