Types of errors (lexical, syntactic, semantic)(MCQs)

Lexical Errors What is a lexical error? A) An error in the meaning of a program B) An error in the structure of a program C) An error in the formation of tokens D) An error in the logic of a program Answer: C) An error in the formation of tokens Which phase of the compiler is responsible for detecting lexical errors? A) Lexical analysis B) Syntax analysis C) Semantic analysis D) Code generation Answer: A) Lexical analysis A lexical error typically occurs when: A) The compiler cannot recognize a sequence of characters as a valid token B) The parser encounters an undefined variable C) The program has a logical inconsistency D) The code does not compile due to missing semicolons Answer: A) The compiler cannot recognize a sequence of characters as a valid token Which of the following can cause a lexical error? A) Misspelled keywords B) Incorrect indentation C) Mismatched parentheses D) Division by zero Answer: A) Misspelled keywords Which of the following tools detects lexical errors? A) Lex (lexical analyzer generator) B) Yacc (parser generator) C) Debugger D) Compiler linker Answer: A) Lex (lexical analyzer generator) What happens when a lexical analyzer encounters an unrecognized character? A) A lexical error is reported B) The program continues execution C) The character is ignored D) The program enters an infinite loop Answer: A) A lexical error is reported Which type of error is caused by a misused operator in source code? A) Lexical error B) Syntax error C) Semantic error D) Runtime error Answer: A) Lexical error When a numeric constant contains invalid characters, which type of error occurs? A) Lexical error B) Semantic error C) Syntactic error D) Logical error Answer: A) Lexical error Which of the following is NOT a possible lexical error? A) Incorrect keyword spelling B) Incorrect token formation C) Integer overflow D) Illegal identifier name Answer: C) Integer overflow A lexical error in a program is detected during which of the following? A) Compilation time B) Runtime C) Program execution D) Memory allocation Answer: A) Compilation time Syntactic Errors What is a syntactic error? A) An error in the structure of a source code statement B) An error in variable declaration C) An error in the logic of the program D) An error in the sequence of tokens Answer: A) An error in the structure of a source code statement Which compiler phase is responsible for detecting syntactic errors? A) Syntax analysis B) Semantic analysis C) Lexical analysis D) Intermediate code generation Answer: A) Syntax analysis Which of the following is a typical example of a syntactic error? A) Mismatched parentheses B) Use of uninitialized variables C) Division by zero D) Invalid memory access Answer: A) Mismatched parentheses A missing semicolon in a C++ program results in which type of error? A) Syntactic error B) Lexical error C) Semantic error D) Logical error Answer: A) Syntactic error Syntactic errors occur due to violations in: A) The grammar rules of the programming language B) The logical flow of the program C) The use of illegal tokens D) Incorrect variable types Answer: A) The grammar rules of the programming language Which of the following tools can help detect syntactic errors? A) Yacc (Yet Another Compiler Compiler) B) Debugger C) Profiler D) Memory checker Answer: A) Yacc (Yet Another Compiler Compiler) An unmatched curly brace in a C++ program is an example of which type of error? A) Syntactic error B) Lexical error C) Semantic error D) Runtime error Answer: A) Syntactic error A missing keyword in an if statement causes which type of error? A) Syntactic error B) Lexical error C) Semantic error D) Runtime error Answer: A) Syntactic error If an else clause is used without a preceding if, which type of error is generated? A) Syntactic error B) Lexical error C) Semantic error D) Logical error Answer: A) Syntactic error An incorrect arrangement of tokens in a statement results in: A) Syntactic error B) Lexical error C) Semantic error D) Runtime error Answer: A) Syntactic error Semantic Errors What is a semantic error? A) An error related to the meaning of a program statement B) An error in the order of tokens C) An error due to a missing operator D) An error due to invalid syntax Answer: A) An error related to the meaning of a program statement Which phase of the compiler detects semantic errors? A) Semantic analysis phase B) Lexical analysis phase C) Syntax analysis phase D) Code generation phase Answer: A) Semantic analysis phase Using a variable before it is initialized is an example of a: A) Semantic error B) Lexical error C) Syntactic error D) Logical error Answer: A) Semantic error If an operation is performed on incompatible data types, what type of error occurs? A) Semantic error B) Lexical error C) Syntactic error D) Runtime error Answer: A) Semantic error A semantic error typically indicates a problem with: A) The logic or meaning of a program B) The structure of code C) The arrangement of tokens D) The memory allocation Answer: A) The logic or meaning of a program Which of the following is an example of a semantic error? A) Adding a number to a string variable B) Mismatched parentheses C) Misspelled keyword D) Missing semicolon Answer: A) Adding a number to a string variable Declaring a variable but not using it in a program results in a: A) Semantic error B) Lexical error C) Syntactic error D) Logical error Answer: A) Semantic error When a function is called with an incorrect number of arguments, which error is triggered? A) Semantic error B) Lexical error C) Syntactic error D) Logical error Answer: A) Semantic error Assigning the wrong data type to a variable results in a: A) Semantic error B) Lexical error C) Syntactic error D) Logical error Answer: A) Semantic error A division of an integer by zero results in which error type at runtime? A) Semantic error B) Lexical error C) Syntactic error D) Logical error Answer: A) Semantic error Comparing Lexical, Syntactic, and Semantic Errors Which error is typically detected first during the compilation process? A) Lexical error B) Syntactic error C) Semantic error D) Logical error Answer: A) Lexical error Which of the following errors is related to the structure of the code but not its meaning? A) Syntactic error B) Lexical error C) Semantic error D) Logical error Answer: A) Syntactic error Which type of error can result from an incorrect function call? A) Semantic error B) Lexical error C) Syntactic error D) Runtime error Answer: A) Semantic error When a variable is declared but not defined, what type of error might occur? A) Semantic error B) Lexical error C) Syntactic error D) Logical error Answer: A) Semantic error Which type of error involves incorrect usage of grammar in the source code? A) Syntactic error B) Lexical error C) Semantic error D) Runtime error Answer: A) Syntactic error Which error type occurs when the program’s meaning does not align with its operations? A) Semantic error B) Lexical error C) Syntactic error D) Logical error Answer: A) Semantic error Misspelled keywords usually result in which error? A) Lexical error B) Syntactic error C) Semantic error D) Logical error Answer: A) Lexical error Which error type is most commonly encountered during program execution rather than compilation? A) Runtime error B) Lexical error C) Syntactic error D) Semantic error Answer: A) Runtime error An undeclared variable used in an expression will cause a: A) Semantic error B) Lexical error C) Syntactic error D) Logical error Answer: A) Semantic error What error is most likely to be caught by a parser? A) Syntactic error B) Lexical error C) Semantic error D) Logical error Answer: A) Syntactic error Advanced Concepts When a variable is declared multiple times in the same scope, what error is caused? A) Semantic error B) Lexical error C) Syntactic error D) Logical error Answer: A) Semantic error Which type of error will occur if you try to use a reserved keyword as an identifier? A) Lexical error B) Semantic error C) Syntactic error D) Runtime error Answer: A) Lexical error A function call with missing arguments leads to: A) Semantic error B) Syntactic error C) Lexical error D) Logical error Answer: A) Semantic error Which of the following is NOT a semantic error? A) Unused variable B) Division by zero C) Incorrect argument type D) Missing semicolon Answer: D) Missing semicolon Which error is caused by a wrong operator precedence in an expression? A) Semantic error B) Syntactic error C) Lexical error D) Runtime error Answer: A) Semantic error Which type of error is detected at the execution time rather than at compile time? A) Runtime error B) Syntactic error C) Lexical error D) Semantic error Answer: A) Runtime error When a loop condition is incorrect, causing an infinite loop, it is an example of: A) Logical error B) Lexical error C) Syntactic error D) Semantic error Answer: A) Logical error What type of error results from using an invalid array index? A) Semantic error B) Lexical error C) Syntactic error D) Runtime error Answer: A) Semantic error Inserting the wrong operator in an expression causes which error? A) Semantic error B) Lexical error C) Syntactic error D) Logical error Answer: A) Semantic error Which error involves declaring a function with incorrect return types? A) Semantic error B) Lexical error C) Syntactic error D) Runtime error Answer: A) Semantic error