Sams Teach Yourself C++ in 21 Days

Exploiting References 271

9

18: cin >> number;

19:

20: result = Factor(number, squared, cubed);

21:

22: if (result == SUCCESS)

23: {

24: cout << “number: “ << number << endl;

25: cout << “square: “ << squared << endl;

26: cout << “cubed: “ << cubed << endl;

27: }

28: else

29: cout << “Error encountered!!” << endl;

30: return 0;

31: }

32:

33: ERR_CODE Factor(int n, int &rSquared, int &rCubed)

34: {

35: if (n > 20)

36: return ERROR; // simple error code

37: else

38: {

39: rSquared = n*n;

40: rCubed = n*n*n;

41: return SUCCESS;

42: }

43: }

Enter a number (0 - 20): 3

number: 3

square: 9

cubed: 27

Listing 9.9 is identical to 9.8, with two exceptions. The ERR_CODEenumeration

makes the error reporting a bit more explicit on lines 36 and 41, as well as the

error handling on line 22.

The larger change, however, is that Factor()is now declared to take references to

squaredand cubedrather than to pointers. This makes the manipulation of these parame-

ters far simpler and easier to understand.

Passing by Reference for Efficiency....................................................................

Each time you pass an object into a function by value, a copy of the object is made. Each

time you return an object from a function by value, another copy is made.

OUTPUT

LISTING9.9 continued

ANALYSIS