Which data structure is used by the compiler for managing variables and their…

Answer: Symbol table

Why this is correct: The symbol table is the compiler's central data structure for storing identifiers (variable names, function names, etc.) and their attributes. It provides a mapping from each name to metadata the compiler needs.

• Common attributes stored: type information, scope level, memory location or offset, declaration line, and other semantic information.

• Core operations supported: insert (on declaration), lookup (on use), and delete (on scope exit if needed).

• Typical implementations: hash tables for fast average-case lookup; balanced trees or scoped chaining when ordering or worst-case guarantees are required.

How the compiler uses it across phases:

1. During parsing and semantic analysis: insert declarations and perform lookups for type checking and scope resolution.

2. During code generation: use stored memory locations and type/layout information to allocate storage and generate correct addressing.

Why the other choices are not correct:

• Binary tree: a possible low-level implementation detail in some cases, but not the conceptual structure used by compilers for managing identifiers and their attributes. The correct conceptual answer is symbol table.

• Link list: inefficient for name-based lookup because it requires linear search; not used as the primary structure for symbol management.

• Parse table: used by parsers to decide parsing actions based on grammar rules and states; it does not store variable attributes.