procedure A(Flag : Boolean) is

1. 
   What parameter passing method(s) does Fortran 77 use for an integer? for an array of integers?
   

2. 
   Fortran does not support all of the parameter passing methods we discussed in class. For this problem, however, I want you to emulate some of them. Write the following swap subroutines to support the main program below.
   

1. 
   swapv – pass by value
   
2. 
   swapr – pass by reference
   
3. 
   swapvr– pass by value result
   
4. 
   swapn- pass by name
   
5. 
   init – initialize value to “2” and list elements to 1,3,5,7,9 respectively
   
6. 
   dump – print value of “value” and “list” to user screen
   

Each swap subroutine takes four arguments:

• 
  argument1 – a variable to be swapped
  
• 
  argument2 – the index into the array that holds argument1 or –1 if argumnet1 is not an array element
  
• 
  argument3 – a variable to be swapped
  
• 
  argument4 – the index into the array that holds argument3 or –1 if argument3 is not an array element
  

For example, swapv(list(1),1,list(2),2) swaps two array elements in the list array. list(1) is to be swapped with list(2). The swap routine may need to know the actual indices for the list elements to ensure that the proper pass by value, pass by value result, or pass by reference semantics are used.

program solutions

common /gvars/ value, list

C Pass by value example

C Pass by reference example

C Pass by value-result example

C Pass by name example

end

3. 
   Are local variables in FORTRAN static or stack dynamic? Are local variables that are INITIALIZED to a default value static or stack dynamic? Show me some code with an explanation to back up your answer. Hint: The easiest way to check this is to have your program test the history sensitivity of a subprogram. Look at what happens when you initialize the local variable to a value and when you don’t. You may need to call more than one subprogram to lock in your answer with confidence.
   

4. 
   Implement a linked list data structure for strings. Include at a minimum the following subroutines:
   

next()
// Precondition: none

setPos(pos)

reset()
// Precondition: none

///////////////////////////////////////////////////////

insert(value)

remove()
// Precondition: none

find(value)

setCurrentItem(value)

getCurrentItem()

///////////////////////////////////////////////////////

getLength()

isEmpty()

erase()
// Precondition: none

and execute the following main program:

program solutions

insert(“Bob”)

sort()

output()

write(*,*) find(“Bob”)

reset()
remove()

output()

erase()

output()

end


Place your solutions for 2,3 and 4 in a single file called “hw5.f”. Attach a hard copy of your code and a screen snapshot of the execution results to the homework assignment you hand in class.