A Level Computer Science OCR Practice Exam

During which phase is a program typically parsed?

1. During code execution

2. During compilation

3. During debugging

4. During testing

The correct answer is: During compilation

Parsing a program primarily occurs during the compilation phase. This is a crucial step where the source code is analyzed and translated into an intermediate representation or machine code. During parsing, the compiler checks the syntax of the code against the rules of the programming language, constructing a syntax tree or abstract syntax tree (AST) that represents the grammatical structure of the code. This ensures that any syntax errors are caught before the code execution phase begins, which is vital for producing a correct and executable program. The other phases mentioned—code execution, debugging, and testing—do not involve parsing in the same way. Code execution is the phase where the compiled code runs, and debugging involves identifying and fixing bugs based on execution output. Testing ensures the program meets its requirements and behaves as expected but does not include the parsing process that occurs during compilation.