Question 1

1. 1. no
   2. no
   3. no
   4. no
2. There are the following three kinds of ambiguity:
   1. Associativity of ";". For instance the string x := 1 ; y := 1 ; z := 1 hat two derivation trees
   2. Precedence between if-then-else and ";". For instance the string if x < y then x := 1 else y := 1 ; z := 1 hat two derivation trees
   3. Precedence between try-catch and ";". For instance the string try x := 0 catch x := 1 ; y := 1 hat two derivation trees
Note: the full solution requires to draw the two different trees for each string. Ask the instructor if you have doubts about how to draw them.

Question 2

1. 
       r |- e1  eval  false   r |- e2  eval  v
      ------------------------------------------
            r |- (e1 and e2) eval false
   
   
       r |- e1  eval  true    r |- e2  eval  v
      ------------------------------------------
             r |- (e1 and e2) eval  v
   
   

2.     if e1 then e2 else false
   

Question 3

1. The final value of z is 5
2. The final value of z is 7

Question 4

1. 
   AR of                            AR of the block  
   caller of p         p            where p is declared
           ^   ------------------      ^ 
        CL |___|_               |      | 
           +-->|                |      |
           |   ------------------      |
           |   |               _|______| SL
           |   |                |
           |   ------------------
           |   |    -----       |<-+---+---+---+ 
           |   |  x | 1 |       |  |   |   |   |          
           |   |    --------    |  |   |   |   |
           |   |  b | true |    |  |   |   |   |
           |   |    --------    |  |   |   |   |
        CL |   ------------------  |   |   |   |
           |                       |   |   |   |
           |          q I          |   |   |   |
           |   ------------------  |   |   |   |
           |___|_               |  |   |   |   |
           +-->|                |  |   |   |   |
           |   ------------------  |   |   |   |
           |   |               _|__|SL |   |   |
           |   |                |      |   |   |
           |   ------------------      |   |   |
           |   |    -----       |      |   |   |
           |   |  x | 2 |       |      |   |   |
           |   |    -----       |      |   |   |
        CL |   ------------------      |   |   |
           |                           |   |   |
           |          r I              |   |   |
           |   ------------------      |   |   |
           |___|_               |      |   |   |
           +-->|                |      |   |   |
           |   ------------------      |   |   |
           |   |               _|______|SL |   |
           |   |                |          |   |
           |   ------------------          |   |
           |   |    ---------   |          |   |
           |   |  b | false |   |          |   |
           |   |    ---------   |          |   |
        CL |   ------------------          |   |
           |                               |   |
           |          q II                 |   |
           |   ------------------          |   |
           |___|_               |          |   |
           +-->|                |          |   |
           |   ------------------          |   |
           |   |               _|__________|SL | 
           |   |                |              |
           |   ------------------              |
           |   |    -----       |              |
           |   |  x | 0 |       |              |
           |   |    -----       |              |
           |   ------------------              |
           |                                   | 
           |          r II                     |
           |   ------------------              |
           |___|_               |              |
               |                |              |
               ------------------              |
               |               _|______________|SL 
               |                |
               ------------------
               |    --------    |
               |  b | true |    |
               |    --------    |
               ------------------    
     
   
       CL = Control Link
       SL = Static  Link
   

2. The value printed is 1

Question 5

1. The value printed is 4
2. The following variables are active during the execution of p():
   • x, global variable of type pointer to int, allocated in the space for the globals, lifetime = entire program
   • y, formal parameter of foo() of type pointer to int, reference to the same location as the one pointed by x, lifetime = execution of foo()
   • z, local variable of foo() of type int, allocated on the stack (in the AR of foo()), lifetime = execution of foo()
   • (anonymous) dynamic variable of type int, allocated on the heap, lifetime = between the execution of "x = new int;" and "delete x;"

Question 6

1. No ML, One DP to the stack
2. No ML, No DP
3. One ML, No DP
4. No ML, One DP to the heap
5. One ML, One DP to the heap