HW 10/24 Solution

Scott: 3.1, 3.5, 3.6, 3.7, 3.11, 3.14

3.1 
Decision                                                 Binding time    
Number of built-in functions                             design

Variable declaration that corresponds                    compile-time
to a particular variable reference (i.e., use)

Maximum length allowed for a constant                    design or compiler implementation
character string

The referencing environment for a subroutine             deep vs shallow binding: design
that is passed as a parameter                            the actual environment: execution

The address of a particular library routine              link

Total amount of space occupied by code                   space for code: compile time
and data                                                 space for static and globals: compile
                                                         space for usage in run-time stack and heap: execution
                                                         
3.5 
C  rules: scope extends from declaration through end of block

print statement            variable
7 (in inner())             a: in main
                           b: in middle

11 (in middle())           a: in main
                           b: in middle

14 (in main())             a: in main
                           b: in main


C# rules: names must be declared before use, scope is throughout the block

7                          a: in inner, but have compile-time error (use before initialization)
                           b: in middle

11                         a: in main
                           b: in middle

14                         a: in main
                           b: in main


3.6
a.   9   4   2   3

b.  
main    g:  <no value>
        sl: null
        dl: null

B       a: 3
        x: 1
        sl:  points to main's frame
        dl:  points to main's frame
        
R       m: 1
(1)     sl: points to B's frame
        dl: points to B's frame

R       m: 2
(2)     sl: points to B's frame
        dl: points to R(1)'s frame

R       m: 3
(3)     sl: points to B's frame
        dl: points to R(2)'s frame

A       n: 3
        sl: points to B's frame
        dl: points to R(3)'s frame
        
c.
A follows its static link chain 2 steps (A -> B -> main, i.e., to main's frame),
then go to offset to g (in main's frame).

3.7
a. Brad's code runs out of memory.
Java has garbage collection, so Brad thinks that when he sets a new value to L 
(his code L = reverse (L)) the objects in the original L list will be collected
by the garbage collector (because with the reassignment to L, nothing points to
the first element of the list L (after Brad's while loop has completed.
But there is no garbage collector in C, so both lists (valid and invalid) will
occupy heap space.

b. Brad's output is strangely corrupted.
Aliasing problem! The library code for insert() and for reverse() both involve
changing the next pointers of a node of L.
3.11
Z is real and declared in R
A is real and is a parameter in R
C is real and is a parameter in R
X is real and declared in P

3.14
a. Static scope: 1 (in main), 1 (in main), 2 (in main), 2 (in main)

b. dynamic scope: 1 (in main), 1 (in main), 2 (in second), 1 (in main)