Compiler Design and Construction - Old Questions
2. List out the major tasks carried out in Lexical Analysis Phase. Convert the following NFA to DFA.
6 marks
|
Asked in 2075
In lexical analysis phase, Lexical Analyzer reads the input characters of the source program, groups them into lexemes, and produces a sequence of tokens for each lexeme. The tokens are then sent to the parser for syntax analysis.
Task carried out in lexical analysis phase are:
- Lexical analyzer reads the input character and produces output sequence of tokens that the Parser uses for syntax analysis.
- Lexical analyzer helps to identify token into the symbol table.
- Lexical Analyzer is also responsible for eliminating comments and white spaces from the source program.
- It also generates lexical errors.
- Lexical analyzer is used by web browsers to format and display a web page with the help of parsed data from JavsScript, HTML, CSS
Second part:
Using the subset construction we have the DFA as:
|
States |
Next states |
|
|
0 |
1 |
|
|
→ *{p} |
{r, q} |
Φ |
|
*{r, q} |
{r, q} |
{r} |
|
*{r} |
{r} |
Φ |
|
Φ |
Φ |
Φ |
Now Transition diagram for above table is:
