error with instantiation in constructor

Question

Hi

i'm still experiment with instantiation and tried this: i moved the instantiation from Main into the constructor (as recommended by Sachin Singh in a previous post). But i get the error "the name 'auto' doesn't exist".

Thanks.

V.

using System;
class Car
{
string model;

public Car()
{
Car auto = new Car();
}

static void Main(string[] args)
{
new Car();
auto.model = "Mustang";
Console.WriteLine(auto.model);
}
}

Aravind Govindaraj · Answer

Please refer these example why we need to instantiate in constructor... using System; class Program { static void Main(string[] args) { IVehicle vehicle = new Car(); vehicle.model = CarModel; Logic logic = new Logic(vehicle); //new Car();//no needed here //auto.model = Mustang; Console.WriteLine(logic.GetModel()); } } public class Logic { private IVehicle _vehicle = null; public Logic(IVehicle vehicle){ // why we need instantiate in constructor //over the logic IVehicle is common it may car or van _vehicle = vehicle; //console.write(vehicle.model); } public string GetModel() { return _vehicle.model; } } //This is common Vehicle Class public class Car : IVehicle { public string model { get;set; } public Car(){} // default constructor } public class Van : IVehicle { public string model { get;set; } public Van(){} // default constructor } //this is base public interface IVehicle { public string model { get;set; } }

Aravind Govindaraj · Answer

using System; class Car { string model; Car auto; // global instance public Car() { auto = new Car(); } static void Main(string[] args) { //new Car();//no needed here auto.model = Mustang; Console.WriteLine(auto.model); } } please follow this

Valerie Meunier · Answer

Thanks but can you fix the error of your own code please? I think it is not possible to fix it because from a static method you need instantiation in order to reach auto . The only solution would be to add Car auto = new Car() ; in Main but then why puting it in the constructor?

Valerie Meunier · Answer

Thanks

Aravind Govindaraj · Answer

please follow the link for the Initiation of the constructor https://www.onlinebuff.com/article_what-is-a-constructor-in-c-and-list-types-of-constructors-in-c_19.html#:~:text=A%20benefit%20of%20using%20aconstructor%20or%20an%20instance%20constructor

Valerie Meunier · Answer

Well as i said i'm experimenting with instantiation and as suggested by your collegue it would be better to put the instantiation into the constructor. So that's what i'm trying here. I personnaly indeed would put it in Main in this case. So my questions are: 1) you gave me a code to perform that but i still get an error. Can you tell me independently of its' better or not to do like this how to fix that error? 2) I know the instantiation can be at class level (better in case of the fields are used in several methods) otherwise at method level (e.g. in Main). But what's the benefit to put it into a constructor like this? Thanks again.

Aravind Govindaraj · Answer

I am not sure why you need to create an instance within the same class. In your case my assumption is your main method suppose to be in class A and you have to create another class as Car. eg. class program { static void main (){ // create a car instance here... also if you wana to use it as console app. yes you will get static issue because your main functional is in statsic. you have to sepeate the layer to avoid this issue } } class Car { }

Valerie Meunier · Answer

I tried both version and in both cases i get the error: an object reference is required for non-static fields ... at line: auto .model in Main.