Compilers

LR Parser

Question 1
Marks : +2 | -2
Pass Ratio : 100%
When there is a reduce/reduce conflict?
If a state does not know whether it will make a shift operation using the production rule i or j for a terminal
If a state does not know whether it will make a shift or reduction operation using the production rule i or j for a terminal
If a state does not know whether it will make a reduction operation using the production rule i or j for a terminal
None of the mentioned
Explanation:
It occurs when If a state does not know whether it will make a reduction operation using the production rule i or j for a terminal.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
The construction of the canonical collection of the sets of LR (1) items are similar to the construction of the canonical collection of the sets of LR (0) items. Which is an exception?
Closure and goto operations work a little bit different
Closure and goto operations work similarly
Closure and additive operations work a little bit different
Closure and associatively operations work a little bit different
Explanation:
Closure and goto do work differently in case of LR (0) and LR (1).
Question 3
Marks : +2 | -2
Pass Ratio : 100%
When ß (in the LR(1) item A -> ß.a,a) is not empty, the look-head _________
Will be affecting
Does not have any affect
Shift will take place
Reduction will take place
Explanation:
There is no terminal before the non terminal beta.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
What is terminal table?
Contains all constants in the program
Is a permanent table of decision rules in the form of patterns for matching with the uniform symbol table to discover syntactic structure
Consist of a full or partial list of the token is as they appear in the program created by lexical analysis and used for syntax analysis and interpretation
Is a permanent table which lists all keywords and special symbols of the language in symbolic form
Explanation:
A permanent database that has entry for each terminal symbols such as arithmetic operators, keywords, punctuation characters such as ‘;’, ‘,’etc Fields: Name of the symbol.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
A loader is a program that _________
Program that places functions into memory and prepares them for execution
Program that automates the translation of assembly language into machine language
Program accepting another program written in a high level language and produces as object program
None of the mentioned
Explanation:
A loader is the part of an operating system that is responsible for loading programs and libraries. It is important in the process of placing the programs into memory and executing them.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
An LR-parser can detect a syntactic error as soon as __________
The parsing starts
It is possible to do so a left-to-right scan of the input
It is possible to do so a right-to-left scan of the input
Parsing ends
Explanation:
Error is found when it the input string is scanned.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
What is the similarity between LR, LALR and SLR?
Use same algorithm, but different parsing table
Same parsing table, but different algorithm
Their Parsing tables and algorithm are similar but uses top down approach
Both Parsing tables and algorithm are different
Explanation:
The common grounds of these 3 parser is the algorithm but parsing table is different.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
Which of the following system program forgoes the production of object code to generate absolute machine code and load it into the physical main storage location from which it will be executed immediately upon completion of the assembly?
Two pass assembler
Load and go assembler
Macro processor
Linker
Explanation:
A load and go assembler generates absolute machine code and loads it to physical memory.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
If a state does not know whether it will make a shift operation or reduction for a terminal is called _________
Shift/reduce conflict
Reduce /shift conflict
Shift conflict
Reduce conflict
Explanation:
As the name suggests that the conflict is between shift and reduce hence it is called shift reduce conflict.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
When ß is empty (A -> ß.,a), the reduction by A-> a is done by _________
If next symbol is a terminal
Only If the next input symbol is a
Only If the next input symbol is A
Only if the next input symbol is a
Explanation:
The next token is considered in this case it’s a.