GATE CS 2021 Set 2 — Question 13

MCQ+1 / -0.33EasySyntax AnalysisCompiler DesignSemantic Analysis

Compiler Design → Semantic Analysis

Last updated 5 September 2026

Question

Consider the following ANSI C program: int main() { Integer x; return 0; } Which one of the following phases in a seven-phase C compiler will throw an error?

Correct answer (C) Semantic analyzer Solution 1. Lexical Analyzer : Identifies tokens. Integer and x are both valid identifiers. 2. Syntax Analyzer : Checks the structure. The statement Integer x; follows the syntactical rule for a variable declaration (Type Identifier;). 3. Semantic Analyzer : Checks for meaning and consistency. It will look up the type Integer . Since Integer is not a built-in type (like int) and has not been defined (e.g., via typedef), the semantic analyzer will throw an error for an undefined type. 4. Optimizer : Only runs on valid code. Turn this into a strength. Explore AI-powered practice and doubt support with Success Tracker.

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Correct answer (C) Semantic analyzer Solution 1. Lexical Analyzer : Identifies tokens. Integer and x are both valid identifiers. 2. Syntax Analyzer : Checks the structure. The statement Integer x; follows the syntactical rule for a variable declaration (Type Identifier;). 3. Semantic Analyzer : Checks for meaning and consistency. It will look up the type Integer . Since Integer is not a built-in type (like int) and has not been defined (e.g., via typedef), the semantic analyzer will throw an error for an undefined type. 4. Optimizer : Only runs on valid code.

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