1. /* Example: StructuresIndirect in CodeBlocks

2. structures as function arguments and return values

3. indirect instances using pointers */

4.

5. #include

6. #include

7. #include

8.

9. struct cplx

10. {

11. double real; /* real part */

12. double imag; /* imaginary part */

13. };

14.

15. struct cplx add(struct cplx* pa, struct cplx* pb); /* function prototype */

16.

17. int main(void)

18. {

19. struct cplx z;

20. time_t rawtime = time(NULL);

21.

22.

23. struct cplx* px= malloc(sizeof(struct cplx));

24. struct cplx* py= malloc(sizeof(struct cplx));

25.

26. px->real = 2.5;

27. px->imag = 5.0;

28. py->real = 3.2;

29. py->imag = -1.7;

30.

31.

32. z = add(px, py);

33. printf("Indirect Instance z = %4.2f + %4.2f j ", z.real, z.imag);

34. printf("Today is %s", ctime(&rawtime));

35.

36. return 0;

37. }

38.

39.

40. struct cplx add(struct cplx* pa, struct cplx* pb)

41. {

42. struct cplx c = *pa; /* can initialise an auto struct variable */

43.

44. c.real += pb->real;

45. c.imag += pb->imag;

46. return c; /* can return a struct value */

47. }

11. Which lines create instances of the structure, what are the structure names?

12. What are the structure pointer names?

13. Which lines initialize the member elements of the structures? How?

14. Which line is the prototype for a function with structure pointer parameters

15. Which lines are the function definition with structure pointer parameters

16. How are the member elements of an unamed (indirect instance) structure dereferenced (how are the values changed)?

17. How is the addition of two structures accomplished?

18. Could a pointer be returned from the function?