Which data structure in a compiler is used for managing information about variables and their attributes?

Match all items in Group 1 with correct options from those given in Group 2.

Group 1

P. Regular expression
Q. Pushdown automata
R. Dataflow analysis
S. Register allocation

Group 2

1. Syntax analysis
2. Code generation
3. Lexical analysis
4. Code optimization

The number of tokens in the following C statement is:

printf("i = %d, &i = %x",i, &i);

Type checking is normally done during