Consider the following pascal program skeleton:

                        var a,x,...;
                        procedure readarray;
                              var i,....;
                              begin
                                             ...:=a...
                              end;
      procedure exchange(...);
                       begin
                                             ...:=a...
                                             ...:=x...
                       end;
      procedure qsort(...);
                       var k,v,...;
                       function partition (...)...;
                              var i,j,...;
                              begin
                              ...:=a...
                              ...:=v...
                              end;
                       begin
                              .
                              .
                       end;
      begin
                       .
                       .
      end; 

Assume that at a given point in time during program execution, following procedures are active: sort, qsort(1,9), qsort(1.3), partition(1,3), exchange(1,3).

Show snapshots of the runtime stack with access links after each of the activations.

Given the following Pascal-like program segment

Procedure A;
  x,y: integer;
   Procedure B;
    x,z: real
    S1
   end B;
   Procedure C;
      i: integer;
       S2
   end C;
end A; 

The variables accessible in S1 and S2 are

Consider the following program in pseudo-pascal syntax. What is printed by the program if parameter a in procedure test 1 is passed as
(i) call-by-reference parameter
(ii) call-by-value-result parameter

     program Example (input, output)
     var b: integer;
     procedure test2:
     begin b:=10; end
    procedure test1 (a:integer):
     begin 	a:=5;
                writeln ('point 1: ', a, b);
                test2;
                writeln ('point 2: ', a, b);
     end
     begin(*Example*)
     b:=3; test1(b);
     writeln('point3:', b);
     end