Compiler Design – Multiple Choice Questions (MCQs)

1. 49. Why is left recursion a problem for top-down parsers?

   • A. It can cause infinite loops
   • B. It makes bottom-up parsing difficult
   • C. It has no impact on parsing
   • D. It simplifies the grammar

2. 50. How can left recursion be eliminated from a grammar?

   • A. By rewriting the grammar using iteration or right recursion
   • B. By removing the problematic production rules
   • C. By changing the parsing technique
   • D. By adding lookahead symbols

3. 51. What is left factoring in a grammar?

   • A. A grammar transformation that groups productions with common prefixes
   • B. A grammar transformation that eliminates left recursion
   • C. A grammar transformation that simplifies the grammar
   • D. A grammar transformation that adds new non-terminals

4. 52. What is the purpose of left factoring?

   • A. To make the grammar suitable for predictive parsing
   • B. To eliminate ambiguity
   • C. To reduce the size of the grammar
   • D. To improve the efficiency of code generation

5. 53. What is a directed acyclic graph (DAG) in compiler design?

   • A. A graphical representation of basic blocks
   • B. A graphical representation of the symbol table
   • C. A graphical representation of the intermediate code that makes explicit the common subexpressions
   • D. A graphical representation of the parse tree

6. 54. What is a basic block?

   • A. A sequence of consecutive statements in which control enters at the beginning and leaves at the end without any halt or possibility of branching except at the end
   • B. A single instruction
   • C. A loop in the program
   • D. A function definition