how should be var type used appropriately in c# ? I'm trying to write my first code using var

Question

I am new to C# and I'm trying to write my first code using var type . as you see below ,I make a array of integers (arr1) then I tried to make a new var type and refer my previous array (arr1 --> int[]) to it . but it occurs some errors that say :

Error CS0236 A field initializer cannot reference the non-static field, method, or property.

is there any helps or hints ?

   using System;
   class VarType
   {
       int[] arr1 = { 1, 2, 3 };
       var varType = arr1;
   }

thanks to helpful comment from Charlieface , I change my code to below it solves another error about another things , but the above error still remains ! what should I do about it ?

using System;
class VarType
{
    int[] arr1 = { 1, 2, 3 };
    public static void Main()
    {
        var varType = arr1;
    }
    
 }

Answer 1

First up, var is not a type. It's a special keyword that tells the compiler to infer the type from the data.

So, the two following are equivalent ways of defining an array:

int[] arr1 = { 1, 2, 3 };
var arr2 = { 1, 2, 3 };

Both arr1 and arr2 are int[] in this example.

The issue with your code is that you're trying to define a field in the class VarType using the var keyword which cannot be used for a field.

Had you written it this way it would work:

class VarType
{
    void SomeMethod()
    {
        int[] arr1 = { 1, 2, 3 };
        var varType = arr1;
    }
}

---

The second example in your question failed because Main was declared static, but the array wasn't. It works if you do this:

class VarType
{
    static int[] arr1 = { 1, 2, 3 };
    public static void Main()
    {
        var varType = arr1;
    }
}

Or like this:

class VarType
{
    int[] arr1 = { 1, 2, 3 };
    public void SomeMethod()
    {
        var varType = arr1;
    }
}