Q1 . Consider the following statements regarding the front-end and back-end of a compiler. S1: The front-end includes phases that are independent of the target hardware. S2: The back-end includes phases that are specific to the target hardware. S3: The back-end includes phases that are specific to the programming language used in the source code. Identify the CORRECT option.
Answer.
(A) Only S1 is TRUE.
(B) Only S1 and S2 are TRUE.
(C) S1, S2, and S3 are all TRUE.
(D) Only S1 and S3 are TRUE.
Solution
The correct answer is:
(B) Only S1 and S2 are TRUE.
Explanation:
- S1: The front-end of a compiler includes phases that are independent of the target hardware. This is true. The front-end deals with tasks like analysis, parsing, and semantic analysis, which are primarily concerned with understanding and processing the source code independently of the target hardware.
- S2: The back-end of a compiler includes phases that are specific to the target hardware. This is true. The back-end is responsible for tasks like code optimization and code generation, which are tailored to the hardware architecture.
- S3: The back-end includes phases that are specific to the programming language used in the source code. This statement is not necessarily true.
While some aspects of the back-end may involve handling language-specific features, the main focus of the back-end is on generating efficient machine code for the target hardware, and not all phases in the back-end are directly tied to the programming language used.
Therefore, option (B) is the correct answer.
Q2 Let SLLdel be a function that deletes a node in a singly-linked list given a pointer to the node and a pointer to the head of the list.Similarly, let DLLdel be another function that deletes a node in a doubly-linked list given a pointer to the node and a pointer to the head of the list. Let n denote the number of nodes in each of the linked list. Which one of the following choices is TRUE about the worst-case time complexity of SLLdel and DLLdel?
(A) SLLdel is O(1) and DLLdel is O(n)
(B) Both SLLdel and DLLdel are O(log(n))
(C) Both SLLdel and DLLdel are O(1)
(D) SLLdel is O(n) and DLLdel is O(1)
Solution
SLLdel (Singly Linked List Delete):
In a singly linked list, to delete a node when given a pointer to the node, we
need to find the previous node to update its next pointer. In the worst case,
we may need to traverse the entire list to find the previous node. Therefore,
the worst-case time complexity of SLLdel is O(n).
DLLdel (Doubly Linked List Delete):
In a doubly linked list, since each node has pointers to both the next and
previous nodes, when given a pointer to a node, we can directly update the
pointers of the neighboring nodes to remove the node. This operation can
be done in constant time, regardless of the total number of nodes in the list.
Therefore, the worst-case time complexity of DLLdel is O(1).
So, the correct answer is that SLLdel is O(n) and DLLdel is O(1).
Q3 Which one of the options given below refers to the degree (or arity) of a relation in relational database systems?
Answer.
(A) Number of attributes of its relation schema.
(B) Number of tuples stored in the relation.
(C) Number of entries in the relation.
(D) Number of distinct domains of its relation schema.
Solution
(A) Number of attributes of its relation schema.
In relational database systems, the degree (or arity) of a relation refers to
the number of attributes (columns) present in the relation schema. Each
attribute represents a specific property or characteristic of the data being
stored in the relation.
Q4 Which one or more of the following CPU scheduling algorithms
can potentially cause starvation?
Answer.
(A) First-in First-Out
(B) Round Robin
(C) Priority Scheduling
(D) Shortest Job First
Solution
(A) First-in First-Out (FIFO) scheduling: This algorithm doesn't cause
starvation. Every process will eventually get its turn, but it might lead to longer waiting times for processes that arrive later.
(B) Round Robin (RR) scheduling: This algorithm also doesn't cause starvation. Each process is given a time slice to execute, and all processes get a fair share of the CPU's time.
(C) Priority Scheduling: This algorithm can potentially cause starvation if higher-priority processes continuously arrive, preventing lower-priority processes from getting a chance to execute.
(D) Shortest Job First (SJF) scheduling: This algorithm can potentially cause starvation if short jobs consistently keep arriving, preventing longer jobs from ever getting a chance to execute.
So, the correct options are (C) Priority Scheduling and (D) Shortest Job
First.
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