实例化

class Lion
{
    private double weight; // only accessible with-in class

    this(double weight)
    {
        this.weight = weight;
    }

    double weightInPounds() const @property // const guarantees no modifications
    // @property functions are treated as fields
    {
        return weight * 2.204;
    }
}

void main()
{
    import std.stdio : writeln;
    auto l = new Lion(100);
    assert(l.weightInPounds == 220.4);

    writeln(l.weightInPounds); // 220.4
}