Problem 2 Solution

Description

At the beginning of class on the due date, submit your neatly presented solution with this page stapled to the front (10points).

Given the following program (in pseudo-like language), construct two control flow graphs for the program. In the first, use maximal basic blocks; in the second, place each statement in its own basic block. In both cases, label the nodes in the graphs with the numbers of the program statements.

procedure sqrt(real x):real real x1,x2,x3,eps,errval;

begin

1. x3 = 1

2. errval = 0.0

3. eps = .001

4. if (x <= 0.0)

5. output(“illegal operand”);
6. return errval;
7. else

8. if (x < 1)

9. x1 = x;

10. x2 = 1;

11. else
12. x1 = eps;

13. x2 = x;

14. endif

15. while ( (x2-x1) >= 2.0*eps ) 16. x3 = (x1+x2)/2.0

17. if ( (x3*x3-x)*(x1*x1-x) < 0)

18. x2 = x3;

19. else

20. x1 = x3;

21. endif;
22. endwhile;
23. return x3;
24. endif;
25. end.

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