difference between circuit switching and packet switching?

When we calculate the delay or overall packets in the system, is there any difference for these two?

The defining example of a circuit-switched network is the early analog telephone network. When a call is made from one telephone to another, switches within the telephone exchanges create a continuous wire circuit between the two telephones, for as long as the call lasts.

Circuit switching contrasts with packet switching which divides the data to be transmitted into packets transmitted through the network independently. In packet switching, instead of being dedicated to one communication session at a time, network links are shared by packets from multiple competing communication sessions, resulting in the loss of the quality of service guarantees that are provided by circuit switching.

In circuit switching, the bit delay is constant during a connection, as opposed to packet switching, where packet queues may cause varying and potentially indefinitely long packet transfer delays. No circuit can be degraded by competing users because it is protected from use by other callers until the circuit is released and a new connection is set up. Even if no actual communication is taking place, the channel remains reserved and protected from competing users.

Source:https://en.wikipedia.org/wiki/Circuit_switching

Circuit switching or "connection-oriented data transmission":

path must be decided before data transmission starts;
completion of transmission can be faster because less
overhead is used for routing data units;
if the connection breaks so does transmission of data.


Packet switching or "connectionless data transmission":

at start of transmission no need to worry about establishing a route;
ability to send data packets over any route means transmission
can be more reliable;
completion of transmission can sometimes be subject to delays
because packets may have to be received over different routes
and must always be re-assembled into correct sequence.