2. For the block-structured C code below, indicate the values assigned to w, x, y, and z. int w, x, y, z int i - 4; intj-5; intj 7; int 8; 3. For the block-structured code of the following figure, assuming the usual static scoping of declarations, give the scope for each of the twelve declarations. (int , x, y, z; Block B1/ ( int x, z; /Block B2 ( int v, x; /* Block B3 / Block B4/ ( int y, z; /* Block B5/ int w, x; 4. Consider the context-free grammar: S->SS ISS a 1 Show how the string aa+a* can be generated by this grammar 2 Construct a parse tree for this string. 3 What language does this grammar generate? Justify your answer 5. Which of the following grammars are ambiguous? 1 S->0S1101 2 S->+SSI-SSIa 35"> S ( S) S |