Having Problem with small Function

computerpublic

Hello, I am trying to learn functions in C#. I wrote the following test functions and I am getting the error: Error 1 An object reference is required for the non-static field, method, or property 'Testing_Functions.Program.Test(double, double, double)' C:\Users\computerpublic\AppData\Local\Temporary Projects\Testing Functions\Program.cs 18 29 Testing Functions.

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

namespace Testing_Functions
{
class Program
{
public Double Test(Double Val1, Double Val2, Double Val3)
{
Double Test_Val = Val1 + Val2 + Val3;
return Test_Val;
}
static void Main(string[] args)
{
Double A = 1, B = 2, C = 3;
Double Result = Test(A,B,C);
}
}
}

Dave Kreskowiak

You have to declare the Test method as "static", just like your Main method. Either that, you have to new up an instance of the Program class and use the Test method through that. Serisouly, this is C# 101 stuff. You really need to pick up a beginners book on C# and work through it.

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Dave Kreskowiak

computerpublic

I am using the a book and I am following the example. I don't know why I am getting the error.

Lost User

Look up the keyword "static", as that is why you are getting that particular error.

Why is common sense not common? Never argue with an idiot. They will drag you down to their level where they are an expert. Sometimes it takes a lot of work to be lazy Please stand in front of my pistol, smile and wait for the flash - JSOP 2012

Lost User

You're trying to call an instance method on an implicit this, but Main is static so there is no this.

Bernhard Hiller

The function "Main" is the start point of the program. When "Main" is called, no instance of any object could yet be created, hence it must be static. From a static method, you can reach other static methods. Or you can create an object. When you create a e.g. new Windows Forms application in Visual Studio, it adds a line to Main: Application.Run(new Form1());. This creates a new object of type Form1. Similarly, you could write another class, create the corresponding object, and call its function, e.g.

namespace Testing_Functions
{
class Addition
{
public Double Test(Double Val1, Double Val2, Double Val3)
{
Double Test_Val = Val1 + Val2 + Val3;
return Test_Val;
}
}
}

and then call it from your Main method:

Addition a = new Addition();
Double Result = a.Test(A,B,C);

DaveyM69

I think it's been explained pretty well already, but just in case... static methods are available without an instance of the class. Non static methods are only available through an instance of the class. This gives you two options in your case. Either 1. Make the Test method static

public static Double Test(Double Val1, Double Val2, Double Val3)

or 2. Create a new instance of the class that holds the method (Program in this case).

Double Result = new Program().Test(A,B,C);

alternative

Program program = new Program();
Double Result = program.Test(A,B,C);

Dave
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