A Level Computer Science OCR Practice Exam

What does syntax analysis determine in programming?

1. Whether a program runs efficiently

2. If the sequence of tokens forms a valid instruction

3. The overall design structure of the program

4. The logical flow of the program

The correct answer is: If the sequence of tokens forms a valid instruction

Syntax analysis is a key phase in the compilation process, where the structure of the code is examined to ensure that it adheres to the grammatical rules of the programming language. This involves taking a sequence of tokens—essentially the individual components of the code, like keywords, identifiers, operators, and symbols—and checking if they are arranged in a valid format according to the language's syntax rules. When a program undergoes syntax analysis, the goal is to determine whether each instruction is well-formed and can be understood by the compiler. If the sequence of tokens does not conform to the expected syntax, it will typically result in syntax errors, preventing the program from being compiled and run. In contrast, determining program efficiency, overall design structure, or logical flow pertains to different areas of programming, such as performance analysis, software design, and flow control analysis. These aspects do not fall within the purview of syntax analysis, which is strictly concerned with the correctness of the code's syntax. Thus, the focus of syntax analysis on validating the structure of instructions is why the indicated answer is the right choice.