Creating a new object in C#-CodePudding

So I have created a car class with objects and constructor and I'm trying to get the values but I'm getting an error which says: There is no argument given that corresponds to the required formal parameter c# This is my class:

public class Car
    {
        private int yearOfProduction;
        private int engineVolume;

        public Car(int yearOfProduction, int engineVolume)
        {
            this.yearOfProduction = yearOfProduction;
            this.engineVolume = engineVolume;
        }

        public int YearOfProduction { get; set; }
    
        public int EngineVolume { get; set; }
    }
}

And my main method:

using System;

namespace Car2
{
    class Program
    {
        static void Main()
        {
            Car car = new Car();
            Console.Write("Year of production: ");
            car.YearOfProduction = int.Parse(Console.ReadLine());
            Console.Write("Engine volume: ");
            car.EngineVolume = int.Parse(Console.ReadLine());
            Console.WriteLine(YearOfProduction);
            Console.WriteLine(EngineVolume);
        }
    }
}

CodePudding user response：

You've got a few different issues here.

Starting with the Car class:

You only have one constructor, no default constructor to hit with new Car(). Adjust your class to something like this:

public class Car
{
    private int yearOfProduction;
    private int engineVolume;

    public Car(int yearOfProduction, int engineVolume)
    {
        this.yearOfProduction = yearOfProduction;
        this.engineVolume = engineVolume;
    }

    public Car() //this is what will be called on new Car()
    {

    }

    public int YearOfProduction { get; set; }

    public int EngineVolume { get; set; }
}

You can otherwise leave the class as is by calling the constructor you provided, which requires two ints, like Car car = new Car(5, 5).

In your Main, the lines

Console.WriteLine(YearOfProduction);
Console.WriteLine(EngineVolume);

Are not referring to the properties of car. You need to adjust that to:

Console.WriteLine(car.YearOfProduction);
Console.WriteLine(car.EngineVolume);

CodePudding user response：

You specify that the class needs two parameters in order to be created: yearOfProduction and engineVolume, both without default value, so both mandatory.

 public Car(int yearOfProduction, int engineVolume)
    {
        this.yearOfProduction = yearOfProduction;
        this.engineVolume = engineVolume;
    }

but you initialize the instance without the parameters:

 Car car = new Car();

For the sanity of your code, remove the initialization, or set default values:

 public Car(int yearOfProduction = 0, int engineVolume = 0)
    {
        this.yearOfProduction = yearOfProduction;
        this.engineVolume = engineVolume;
    }

Or initialize with values:

 Car car = new Car(0,0);

CodePudding user response：

You only constructor for Car as you have written it is:

public Car(int yearOfProduction, int engineVolume)

This means you can only Create an instance of Car if you give it yearOfProduction and engineVolume. Something like this:

int year = 1994;
int volume = 2400;
Car car = new Car(year,volume);

Alternatively you could provide a second constructor:

public Car()
{
    YearOfProduction = 1994;
    EngineVolume = 2400;
}

By the way, when you say "a car class with objects" I think what you mean is "a car class with some fields and properties". Also, your fields aren't doing anything and seem redundant.

CodePudding user response：

The problem is that your constructor is expecting two values

public Car(int yearOfProduction, int engineVolume)

And you instantiate the class with none:

Car car = new Car();

Given the way you instantiate the class, you should add (or replace, depending on your use cases) the following constructor:

public Car()
{
//some stuff
}