Computer Science 5641
Compiler Design
Homework Assignment 4 (20 points)
Due November 21, 2002

1. [5] Do exercise 6.3 from the textbook.
2. [5] Construct a program using C or C++ syntax that has different output assuming parameters are passed by (1) value, (2) reference or (3) value-result.
3. [5] At the points labeled (A) through (E) show the symbol table structure that would exist in analyzing this program using (1) a symbol table using a list of hashtables and (2) a symbol table using a hashtable of lists.

   Assume the most closely nesting scope rule for resolving uses and that each function introduces one new scope for both its parameters and local variables.

   int X;
   double Y;
   
   int F (char X, int Z) {
     char Y;
     /* (A) */
   
     {
       double X, Y;
       int W;
   
       /* (B) */
     }
   
     char W;
   
     /* (C) */
   
   }
   
   /* (D) */
   
   double G (int Z) {
     char X;
   
     f(X,Z);
   
     /* (E) */
   
   }
   
    [5] Many languages allow functions to be passed as parameters.  Using C++'s
    mechanism for passing functions as parameters, discuss how having these types
    would be dealt with in a symbol table and during type checking.