PROCEDURE (n: Node) Add(VAR datakey: Data);

        VAR
            temp: Data;

    BEGIN
        NEW(n^.data2);
        Out.String("Entering Add");
        NEW(temp);
        IF (datakey^.value > n^.data1^.value) THEN
            Out.String("Casus 1"); Out.Ln();
            IF (n^.data2 = NIL) THEN
                NEW(n^.data2);
                n^.data2^.value := datakey^.value; Out.Int(1,0);
            ELSIF (n^.data2 # NIL) THEN
                IF ((datakey^.value > n^.data1^.value) & (n^.data2^.value > datakey^.value)) THEN
                    IF ((n^.middle = NIL) & (n^.IsFull())) THEN
                        NEW(n^.overflowdata);
                        n^.overflowdata^.value := n^.data2^.value;
                        n^.data2^.value := datakey^.value;
                        Out.String("Splitting");
                        Out.Ln();
                        Split(n);
                    ELSIF (n^.middle # NIL) THEN
                        n^.middle^.Add(datakey); Out.Int(2,0);
                    END;
                END;
            ELSE
                Out.String("Hier zou ik nooit moeten komen. #1");
                Out.Ln();
            END;
        ELSIF (n^.data2 # NIL) THEN
                IF (datakey^.value > n^.data2^.value) THEN
                    Out.String("Casus 2"); Out.Ln();
                    IF (n^.right # NIL) THEN
                        n^.right^.Add(datakey); Out.Int(3,0);
                    ELSIF ((n^.right = NIL) & (n^.IsFull())) THEN
                        NEW(n^.overflowdata);
                        n^.overflowdata^.value := datakey^.value;
                        Out.String("Splitting.");
                        Out.Ln();
                        Split(n);
                    ELSE
                        Out.String("Hier zou ik nooit moeten komen. #2");
                        Out.Ln();
                    END;
                END;
ELSIF (datakey^.value < n^.data1^.value) THEN
            Out.String("Casus 3"); Out.Ln();
            IF (n^.data2 = NIL) THEN
                NEW(n^.data2);
                temp^.value := n^.data1^.value;
                n^.data1^.value := datakey^.value;
                n^.data2^.value := temp^.value; Out.Int(4,0);
            ELSIF ((n^.IsFull()) & (n^.left # NIL)) THEN
                n^.left^.Add(datakey);Out.Int(5,0);
            ELSIF ((n^.IsFull()) & (n^.left = NIL)) THEN
                NEW(n^.overflowdata);
                n^.overflowdata^.value := n^.data2^.value;
                n^.data2^.value := n^.data1^.value;
                n^.data1^.value := datakey^.value;
                Out.String("Splitting.");
                Out.Ln();
                Split(n);
            ELSE
                Out.String("Hier zou ik nooit moeten komen. #3");
                Out.Ln();
            END;
        ELSE
            Out.String("Ik heb dit helemaal fout gedaan.");
            Out.Ln();
        END;
    END Add;