Q:

Why is there only one line for the classical register?

So I am wondering why this "Quantum Teleportation Algorithm" from Qiskit - Programming on Quantum Computers Ep 5 is represented differently when I draw it (on the left in the image above) compared to when they draw it (on the right in the image above), i.e. my result has only one $c$ line and the result from the video has separate lines for $c_0$, $c_1$, and $c_2$.
I would assume that this is something that was simply changed in development of Qiskit, but then I am wondering why they would make this change.
Again, my assumption would be that there are no controlled gates on classical bits but only links from the quantum register to the classical register, hence, it is not needed to display separate lines.

A:

This can be done by passing a style to the drawer, setting the cregbundle to be False as the default is True. For example, given the circuit qc we can draw all the classical registers as follows :
qc.draw(output='mpl', filename='no_bundle.png', style={'cregbundle': False})
However, it is worth noting that only the mpl drawer supports setting things using a style dictionary like this.

