Lexical vs Syntax Error

Question

 

Comments

Yeah brother that would be really helpful

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i don't have it, but this may helps you.

Limitations of Syntax Analyzers

 in the link https://www.tutorialspoint.com/compiler_design/compiler_design_syntax_analysis.htm

 

Semantic Errors

in the link https://www.tutorialspoint.com/compiler_design/compiler_design_semantic_analysis.htm

 

https://www.tutorialspoint.com/compiler_design/compiler_design_error_recovery.htm

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this page is really helpful

https://www.geeksforgeeks.org/error-detection-recovery-compiler/

Answer 1

int a b;= long identifier it can detect during lexical analysis

int 1ab2;=I'll formed numeric literal it can detect during lexical analysis

in t a b;= long identifier it can detect during lexical analysis

D) All the above

Comments

Please explain long identifier error.

Answer 2

C will be right option

<1ab2> is invalid token as it is neither keyword nor can be an identifier as 1st  character is a number.

Answer 3

All of them are Lexical Errors. Lexical analysis is implemented using Finite Automata.  

Option A: int a b;
Start->int->a->"Expected either ; or = but got whitespace." (Error) Generated Tokens: 2

Option B: in t a b;
Start->i->n->"Expected t but got whitespace" (Error) Generated Tokens: 0

Option C: int 1ab2;
Start->int->"Expected a permitted character but got 1"->a "Didn't expect a character after a number" (Error) Generated Tokens: 1

Explanation of Option C: A parser doesn't support Backtracking. After getting 1 (Which was not permitted) the compiler got a which means that it has to backtrack.

 

Answer 4

Option D ) All of the above.

Answer 5

OPTION C, is the answer.

Because an identifier must always start with an underscore or a letter. Since  (1ab2) starts with a number, it obviously gives a lexical error.

Other explaination:

Since OPTION A is correct, A and D are ruled out.

and in OPTION B, (in t a b;), we get 5 tokens.

Answer 6

• Lexical : name of some identifier typed incorrectly

• Syntactical : missing semicolon or unbalanced parenthesis

• Semantical : incompatible value assignment

• Logical : code not reachable, infinite loop