Giving vala a variable to function doesn't pass right

Question

Helo,

I've the following code:

                    int column2 = 0 + ((z - 1) % 2 * 2);

The variable column2 has definitive the value 2.

                    grid.attach(label_name, column2, row2, 1, 1);

This doesn't attach the label to column 2. It is still column 0. But if I do:

                    grid.attach(label_name, 2, row2, 1, 1);

it works.

What am I doing wrong? It's tricky for me.