Teach Yourself Borland C++ in 14 Days - portal

90 Day 3
NOTE
Default parameters are helpful for many reasons. For one thing, they make your life easier.
You may have a function that you call with the same parameters 99 percent of the time. By
giving it default parameters, you shorten the amount of typing required each time you make
a call to the function. Whenever you want to supply parameters other than the defaults, all
you have to do is plug in values for the default parameters.
Any default parameters must come at the end of the function’s parameter
list. The following is not a valid function declaration:
int MyFunction(int x, int y = 10, int t = 5, int z);
In order for this function declaration to compile, the default parameters
must be moved to the end of the function list:
int MyFunction(int x, int z, int y = 10, int t = 5);
If you don’t put the default parameters at the end of the parameter list,
the compile will generate a compiler error.
Class Member Functions
NEW TERM
As you will find out in this section, classes can contain their own functions. Such
functions are called member functions because they are members of a class.
Class member functions follow the same rules as regular functions: They can be overloaded,
they can have default parameters, they can take any number of parameters, and so on.
Class member functions can be called only through an object of the class to which the
function belongs. To call a class member function, you use the direct member operator (in
the case of local objects) or the indirect member operator (for dynamically created objects)
just like you did when accessing data members of a structure on Day 2. For example, let’s say
that you had a class called Airplane that was used to track an airplane for aircraft-control
software. That class would probably have the capability to retrieve the current speed of a given
aircraft via a function called GetSpeed(). The following example illustrates how you would
call the GetSpeed() function of an Airplane object:
Airplane plane; // create a class instance
int speed = plane.GetSpeed();
cout