# 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.

• In the image on the left the 3 classical register lines are bundled together (notice a slash with 3 written above it). It's just notation. – Sanchayan Dutta Dec 7 '19 at 16:53
• @SanchayanDutta I reckoned that, but do you know why or if there is an option in Qiskit to represent them separately? I could not find anything on it. – creativecreatorormaybenot Dec 7 '19 at 16:55
• Oh, I misinterpreted your question. They might be using a different environment. Anyway, I don't know much about Qiskit and I rarely use it. Let's wait for an answer from the Qiskit team (they check this site regularly). – Sanchayan Dutta Dec 7 '19 at 17:03

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.