1.2. History of C and C++

C++ evolved from C, which evolved from two previous programming languages, BCPL and B. BCPL was developed in 1967 by Martin Richards as a language for writing operating systems software and compilers for operating systems. Ken Thompson modeled many features in his language B after their counterparts in BCPL and he used B to create early versions of the UNIX operating system at Bell Laboratories in 1970.

The C language was evolved from B by Dennis Ritchie at Bell Laboratories. C uses many important concepts of BCPL and B. C initially became widely known as the development language of the UNIX operating system. Today, most operating systems are written in C and/or C++. C is available for most computers and is hardware independent. With careful design, it is possible to write C programs that are portable to most computers.

The widespread use of C with various hardware platforms unfortunately led to many variations. This was a serious problem for program developers, who needed to write portable programs that would run on several platforms. A standard version of C was needed. The American National Standards Institute (ANSI) cooperated with the International Organization for Standardization (ISO) to standardize C worldwide; the joint standard document was published in 1990 and is referred to as ANSI/ISO 9899:1990.

C99 is the latest C standard. It was developed to evolve the C language to keep pace with today's powerful hardware and with increasingly demanding user requirements. The C99 Standard is more capable (than earlier C Standards) of competing with languages like Fortran for mathematical applications. C99 capabilities include the long long type for 64-bit machines, complex numbers for engineering applications and greater support of floating-point arithmetic. C99 also makes C more consistent with C++ by enabling polymorphism through type-generic mathematical functions and through the creation of a defined boolean type. For more information on C and C99, see our book C How to Program, Fifth Edition and our C Resource Center (located at www.deitel.com/C/).

C++, an extension of C, was developed by Bjarne Stroustrup in the early 1980s at Bell Laboratories. C++ provides a number of features that "spruce up" the C language, but more importantly, it provides capabilities for object-oriented programming.

You'll be introduced to the basic concepts and terminology of object technology in Section 1.10. Objects are essentially reusable software components that model items in the real world. Software developers are discovering that a modular, object-oriented design and implementation approach can make them much more productive than can previous popular programming techniques. Object-oriented programs are easier to understand, correct and modify. You'll begin developing customized, reusable classes and objects in Chapter 3, Introduction to Classes and Objects. This book is object oriented, where appropriate, from the start and throughout the text. This gets you "thinking about objects" immediately and mastering these concepts more completely.

We also provide an optional automated teller machine (ATM) case study in the Software Engineering Case Study sections of Chapters 1–7, 9 and 13, and Appendix E, which contains a complete C++ implementation. The case study presents a carefully paced introduction to object-oriented design using the UML—an industry standard graphical modeling language for developing object-oriented systems. We guide you through a first design experience intended for the novice object-oriented designer/programmer. Our goal is to help you develop an object-oriented design to complement the object-oriented programming concepts you learn in this chapter and begin implementing in Chapter 3.