My question is why we still need to use command ip default-gateway since the router still can reach the switch from other network without the ip default-gateway. If you don't add the ip default-command to the switch, the switch can only reach hosts in the local subnet (192.168.0.0/24) and no other subnet.
Tech articles: How to Find Default Gateway of My Computer Jan 06, 2017 Default Gateway, finding other IP networks - Homenet Howto To find its local router the computer needs a so-called Default Gateway, sometimes simply called a Gateway. A Default Gateway is always a router that can connect to more than one IP network and can route traffic between those IP networks. The router will have its …
Speaking for IOS, using the cellular connection - you don’t. If it’s for WiFi, it’s listed under the WiFi-settings as router.
How to Find Default Gateway in Linux – How to Linux Nov 04, 2014
Gateway Router Passwords - port forward
Oct 22, 2012 Configuring the Switch IP Address and Default Gateway - Cisco