A Level Computer Science OCR Practice Exam

How does semantic analysis differ from syntax analysis?

1. Semantic analysis checks the meaning while syntax analysis checks the structure

2. They are the same process with different names

3. Syntax analysis ensures code efficiency while semantic does not

4. Semantic analysis is conducted before syntax analysis

The correct answer is: Semantic analysis checks the meaning while syntax analysis checks the structure

Semantic analysis and syntax analysis are two distinct phases of the compilation process in programming languages. The correct choice describes how these two analyses serve different purposes within this process. During syntax analysis, the compiler checks the code against the grammatical rules of the programming language to ensure that the structure of the code is correct. It verifies whether the code follows the correct syntax, using grammar rules to determine whether the arrangement of symbols and tokens conforms to the expected patterns. Essentially, it ensures that the code is properly structured to make sense within the language's formal constraints. On the other hand, semantic analysis is concerned with the meaning of the code. It checks that the code makes logical sense in its context and adheres to the language's semantic rules. This includes confirming that variables are defined before they are used, that operations are performed on compatible data types, and that functions are called with the correct arguments. By focusing on how the pieces of code interact and ensuring the intended functionality aligns with the meanings assigned, semantic analysis adds a crucial layer of validation beyond just structure. The incorrect options highlight misunderstandings about the processes involved. The notion that they are the same process or have different names misconstrues their unique roles, while the idea that syntax checks for code efficiency misrepresents