Chapter 3, Problem 2E

Explanation of Solution

Justification:

• The recursion feature is absent in FORTRAN 77. So there can be more than one live instance of local variable of the particular subroutine.
• Algol and its successor require a stack to store multiple copies.
• The following program statements would not work correctly with statically allocated local variables.

    //Defining the function sum and passing the arguments.

    function sum(f, small, large)

    {

        //Making condition for if.

         if small = large

        //Returning the small value.

         return f(small)

        //Else statement

        else

        //Returning computed small value.

        return f(small) + sum(f, small + 1, large)

    }

  Explanation:

• Now the sum() functions needs to remember the value of small while recursive call.
  • In Section 6.6.1, it is potential to write a tail recursive version of sum that doesn’t need to remember anything while recursive call, but only if one is willing to change the calling signature of the function or to exploit the associativity of addition...