import std.stdio;
import std.conv;

class LinkedList
{
private:
    struct Node
    {
        int val;
        Node* next = null;

        this(int newVal)
        {
            val = newVal;
        }
    }

    Node* root = null;

public:
    void append(int newVal)
    {
        if (root is null)
        {
            root = new Node(newVal);
            return;
        }

        auto curr = root;
        while (curr.next !is null)
        {
            curr = curr.next;
        }
        curr.next = new Node(newVal);
    }

    override string toString()
    {
        string s;
        auto curr = root;
        while (curr !is null)
        {
            writeln(s);
            s ~= to!string(curr.val) ~ " ";
            curr = curr.next;
        }
        return s;
    }
}

void main()
{
    LinkedList l;

    for (int i = 0; i < 10; ++i)
        l.append(i);

    writeln(l);
}