Sams Teach Yourself C in 21 Days

Polymorphism, encapsulation, and inheritance are all a part of this listing. A class called

squareis defined in lines 5 to 12. The details of this class will be discussed on Bonus

Day 3. For now, notice that the declaration contains both functions (lines 7, 8, 10, and

11) and data (line 9). This enables all the features of a square to be encapsulated into one

place. You can see in lines 22 and 28 that there are two different ways of setting up the

squareclass. Inheritance is also illustrated in the listing. The cubeclass inherits from the

squareclass as you can see in line 15. Finally, you can see that reuse is also a feature of

this listing. The cube declaration reuses the square functionality. Additionally, the cube

and square declarations have been written to where they could easily be reused in other

listings. This will all be clearer after Bonus Day 3 when you cover C++ classes and

objects.

The Relationship of C++ to C ......................................................................

C++ is a superset of C. This means that all the features of C are available in C++. All the

features of C++ are not, however, available in C. If you look back at Listing B1.2, you

should be able to determine what most of the code does. Only a few of the constructs

will be new to you.

C++ was created in order to have a programming language that is easier to use with the

object-oriented constructs. Keywords such as classandtemplateare added to make

creating objects and reusable code easier. Additionally, keywords such as tryandcatch

are added to make finding and preventing errors easier. All these changes helped to cre-

ate a language that is much more powerful as well as reusable.

C++ Programs ..............................................................................................

Just like C, C++ is used for more than creating executable programs. The most common

types of programs created with C++ are presented in Table B1.1.

TABLEB1.1 C++ program types

Program Type Description

executables Programs that can be run by an operating system

libraries Routines created to link to other programs being created

dynamic linked libraries Routines created that can reside in memory and be linked to other

programs at runtime

controls Routines created that can be used in the creation of other pro-

grams

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