C# 重载操作符的实现

namespace ProCSharp
{
    struct Vector : IEquatable<Vector>    // For value type performance 
    {
        public Vector(double x, double y, double z)
        {
            X = x;
            Y = y;
            Z = z;
        }
        public Vector(Vector v)
            : this(v.X, v.Y, v.Z)
        {
        }

        public double X { get; }
        public double Y { get; }
        public double Z { get; }
        public override string ToString() => $"( {X}, {Y}, {Z} )";

        public static Vector operator +(Vector left, Vector right)
            => new Vector(left.X + right.X, left.Y + right.Y, left.Z + right.Z);

        public static Vector operator *(double left, Vector right)
            => new Vector(left * right.X, left * right.Y, left * right.Z);

        public static Vector operator *(Vector left, double right)
            => right * left;

        public static double operator *(Vector left, Vector right) 
            => left.X * right.X + left.Y * right.Y + left.Z * right.Z;

        // implement IEquatable<Vector> for value type
        public bool Equals(Vector other)
        {
            if (object.ReferenceEquals(other, null))
                return false;

            if (object.ReferenceEquals(this, other))
                return true;

            return (this.X == other.X && this.Y == other.Y && this.Z == other.Z);
        }

        // implement override equals
        public override bool Equals(object obj)
            => Equals((Vector)obj);

        public static bool operator ==(Vector left, Vector right)
            => left.Equals(right);

        public static bool operator !=(Vector left, Vector right)
            => !left.Equals(right);

        public override int GetHashCode() 
            => X.GetHashCode() ^ Y.GetHashCode() ^ Z.GetHashCode();

        public static void TestVector()
        {
            var vect1 = new Vector(3.0, 3.0, -10.0);
            var vect2 = new Vector(3.0, 3.0, -10.0);
            var vect3 = new Vector(2.0, 3.0, 6.0);
            Console.WriteLine($"vect1 == vect2 returns {(vect1 == vect2)}");
            Console.WriteLine($"vect1 == vect3 returns {(vect1 == vect3)}");
            Console.WriteLine($"vect2 == vect3 returns {(vect2 == vect3)}");
            Console.WriteLine();
            Console.WriteLine($"vect1 != vect2 returns {(vect1 != vect2)}");
            Console.WriteLine($"vect1 != vect3 returns {(vect1 != vect3)}");
            Console.WriteLine($"vect2 != vect3 returns {(vect2 != vect3)}");
        }
    }
}