Sams Teach Yourself C++ in 21 Days

16: cout << “. Square(“ << x << “): “;

17: cout << Square(x);

18: cout<< “. Cube(“ << x << “): “;

19: cout << Cube(x) << “.” << endl;

20: }

21: return 0;

22: }

Enter a number (0 to quit): 1

You entered: 1. Square(1): 1. Cube(1): 1.

Enter a number (0 to quit): 2

You entered: 2. Square(2): 4. Cube(2): 8.

Enter a number (0 to quit): 3

You entered: 3. Square(3): 9. Cube(3): 27.

Enter a number (0 to quit): 4

You entered: 4. Square(4): 16. Cube(4): 64.

Enter a number (0 to quit): 5

You entered: 5. Square(5): 25. Cube(5): 125.

Enter a number (0 to quit): 6

You entered: 6. Square(6): 36. Cube(6): 216.

On lines 3 and 4, two inline functions are defined:Square()and Cube(). Each is

declared to be inline, so like a macro function, these are expanded in place for

each call, and no function call overhead occurs.

As a reminder, expanded inline means that the content of the function is placed into the

code wherever the function call is made (for example, on line 17). Because the function

call is never made, there is no overhead of putting the return address and the parameters

on the stack.

On line 17, the function Squareis called, as is the function Cubeon line 19. Again,

because these are inline functions, it is exactly as if this line had been written like this:

16: cout << “. Square(“ << x << “): “ ;

17: cout << x * x ;

18: cout << “. Cube(“ << x << “): “ ;

19: cout << x * x * x << “.” << endl;

OUTPUT

772 Day 21

LISTING21.6 continued

ANALYSIS

DOuse CAPITALS for your macro names.

This is a pervasive convention, and other

programmers will be confused if you

don’t.

DOsurround all arguments with paren-

theses in macro functions.

DON’Tallow your macros to have side

effects. Don’t increment variables or

assign values from within a macro.

DON’T use #definevalues when a con-

stant variable will work.

DO DON’T