TCS Placement: Sample Questions 341 - 342 of 502
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Question 341
Explanation
- Create two pointers, and set both to the start of the list. Update each as follows:
- while (pointer1) {pointer1 = pointer1 ⇾ next; pointer2 = pointer2 ⇾ next; if (pointer2) pointer2 = pointer2 ⇾ next; if (pointer1 == pointer2) {print ( “circular” ) ;} }
- If a list is circular, at some point pointer2 will wrap around and be either at the item just before pointer1, or the item before that. Either way, it՚s either 1 or 2 jumps until they meet.
Question 342
Explanation
The Data Link Layer transforms the physical layer, a raw transmission facility, to a reliable link and is responsible for node-node delivery. It provides following functions:
- Framing
- Frames are streams of bits received from the network layer broken into manageable data units.
- This division of stream of bits is done by Data Link Layer.
- Physical Addressing
The Data Link layer adds a header to the frame that defines physical address of the sender or receiver of the frame, if the frames are to be distributed to different systems on the network.
- Flow Control
- Provides a flow control mechanism to avoid a fast transmitter from running a slow receiver by buffering the extra bit.
- Prevents overflow at the receiver side.
- Error Control
- Adds a trailer at the end of the frame for error control.
- Also, duplication of frames is prevented by using this mechanism.
- Access Control
Protocols of this layer determine the devices that can control the link at any given time- when two or more devices are connected to the same link.