Answer:
b. adds to Iterator the ability to move backwards in the collection
Explanation:
In Java programming, the ListIterator interface adds to Iterator the ability to be bidirectional i.e move backwards and forward in the collection and it is a sub-interface of the Iterator interface.
The ListIterator interface makes it possible to modify any list during iteration and determine its position in the list.
Answer:
Draft
Explanation:
Draft is a specific folder in email that is meant to store partially finished mails and mails which has been created but is not sent . Draft folders helps in reducing rework on the mail if one is interrupted while writing the mail. Another purpose of draft folder was that if anyone accidentally closes the mail writing section then the content of mail is not lost and can be easily be obtained in draft folder. It also helps in tracking unsent and unfinished mail for the user.
Since, message written by Alexa is saved at different points but is not sent then if the mail is to be sent, then one needs to look for that mail in Draft folder.
Answer:
MAC Addresses (Destination and Source MAC address)
Explanation:
A switch has 3 primary functions:
- Forward frames
- Learn addresses
- Avoid loops
An Ethernet frame has the header, data and trailer and there are two specific fields in the header that helps the switch to know where to send data in future transmissions.
- destination MAC address
- source MAC address
every Ethernet frame has this and when the frame hits a switch or any device, any device can look at it ( an Ethernet frame ) and know where it is suppose to go and where it came from.
Every switch has a MAC address table where it stores MAC addresses of different computers on the network.
Example:
When a PC1 sends a frame to PC2 through a switch, the switch looks at the header of the Ethernet frame for the source mac address and adds the source MAC address to its MAC address table and also the port that it came through.
simply put:
A switch looks at the source MAC address to see if it knows it already, if it does. Great! no need to add it again to it's address table.
If it doesn't, it adds it's source address and the port that the frame came from.
This basically how the switch populates its MAC address table.
Answer:
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