What is the output of lexical analyzer MCQ questions?
What is the output of lexical analyzer? Explanation: A lexical analyzer coverts character sequences to set of tokens. 2.
Which tool can be used for generating lexical analyzers?
FLEX (fast lexical analyzer generator) is a tool/computer program for generating lexical analyzers (scanners or lexers) written by Vern Paxson in C around 1987.
How do we implement lexical analyzer explain with example?
Lexical Analysis is the first phase of the compiler also known as a scanner. It converts the High level input program into a sequence of Tokens….Example of tokens:
- Type token (id, number, real, . . . )
- Punctuation tokens (IF, void, return, . . . )
- Alphabetic tokens (keywords)
What is the purpose of lexical analyzer?
The lexical analysis is the first phase of the compiler where a lexical analyser operate as an interface between the source code and the rest of the phases of a compiler. It reads the input characters of the source program, groups them into lexemes, and produces a sequence of tokens for each lexeme.
What is the input of lexical analyzer?
Explanation: Lexical analyser’s Input is Source Code. Explanation: Lexical Analysis Identifies Different Lexical Units in a source Code.
What is the output of lexical analyzer?
(I) The output of a lexical analyzer is tokens.
How does a lexical analyzer detect errors?
A lexer contains tokenizer or scanner. If the lexical analyzer detects that the token is invalid, it generates an error. The role of Lexical Analyzer in compiler design is to read character streams from the source code, check for legal tokens, and pass the data to the syntax analyzer when it demands.
Why use separate tokens and lexemes?
Lexeme is basically the unit of a token and it is basically sequence of characters that matches the token and helps to break the source code into tokens. For example: If the source is x=b , then the lexemes would be x , = , b and the tokens would be , <=> , . An answer should be more specific.
What is the output of lexical Analyser?
(I) The output of a lexical analyzer is tokens. (II) Total number of tokens in printf(“i=%d, &i=%x”, i, &i); are 10. (III) Symbol table can be implementation by using array, hash table, tree and linked lists. So, option (D) is correct.
What are the issues of lexical analyzer?
Issues in Lexical Analysis 1) Simpler design is the most important consideration. The separation of lexical analysis from syntax analysis often allows us to simplify one or the other of these phases. 2) Compiler efficiency is improved. 3) Compiler portability is enhanced.
What is the output of lexical analyser?
How to generate a lexical analyzer using Lex compiler?
Step 1: An input file describes the lexical analyzer to be generated named lex.l is written in lex language. The lex compiler transforms lex.l to C program, in a file that is always named lex.yy.c. Step 3: The output file a.out take a stream of input characters and produce a stream of tokens.
What is a lexical analyzer?
A Lexer takes the modified source code which is written in the form of sentences. In other words, it helps you to convert a sequence of characters into a sequence of tokens. The lexical analyzer breaks this syntax into a series of tokens. It removes any extra space or comment written in the source code.
How does the lexical analyzer break the source code into tokens?
Explanation: The lexical analyzer breaks these syntaxes into a series of tokens, by removing any whitespace or comments in the source code. 3. If the lexical analyzer finds a token invalid then? Explanation: If the lexical analyzer finds a token invalid, it generates an error. 4. When the lexical analyzer read the source-code, it scans the code?
Which tool/computer program for generating lexical analyzers (scanners or lexers) written by Vern Paxson in C?
Which tool/computer program for generating lexical analyzers (scanners or lexers) written by Vern Paxson in C around 1987? Explanation: FLEX (fast lexical analyzer generator) is a tool/computer program for generating lexical analyzers (scanners or lexers) written by Vern Paxson in C around 1987.