C# Structs: Unassigned local variable?

c#, struct

Solution

Well, are X and Y properties (rather than fields)? If so, that's the problem. Until all the fields within `x` are definitely assigned, you can't call any methods or properties.

For instance:

public struct Foo
{
    public int x;
    public int X { get { return x; } set { x = value; } }
}

class Program
{
    static void Main(string[] args)
    {
        Foo a;
        a.x = 10; // Valid

        Foo b;
        b.X = 10; // Invalid
    }
}

Is `Vec2` your own type? Do you have access to the fields involved, or only the properties?

If it's your own type, I would strongly urge you to try to stick to immutable structs. I know managed DirectX has some mutable structs for getting as close to optimal performance as possible, but that's at the cost of strange situations like this - and much worse, to be honest.

I would personally give the struct a constructor taking X and Y:

 Vec2 x = new Vec2(det * (a22 * b.X - a12 * b.Y),
                   det * (a11 * b.Y - a21 * b.X));

Problem

From the documentation: Unlike classes, structs can be instantiated without using a new operator. So why am I getting this error: Use of unassigned local variable 'x' When I try to do this? ``` Vec2 x; x.X = det * (a22 * b.X - a12 * b.Y); x.Y = det * (a11 * b.Y - a21 * b.X); ``` Where `Vec2 x` is a struct?

Original source