C Tutorial for Beginners
Introduction of C
In "C Tutorial for Beginners" we provide all the details and information which is very important in every exam. The C programming language was originally developed by Dennis Ritchie of Bell Laboratories, and was designed to run on a PDP-11 with a UNIX operating system. Although it was originally intended to run under UNIX, there was a great interest in running it on the IBM PC and com-patibles, and other systems. C is excellent for actually writing system level programs, and the entire Applix 1616/OS operating system is written in C (except for a few assembler routines). It is an excellent language for this environment because of the simplicity of expression, the compactness of the code, and the wide range of applicability.
One experienced C programmer made the statement, "You can program anything in C", and the statement is well supported by my own experience with the language. Programming in C is a tremendous asset in those areas where you may want to use Assembly Language, but would rather keep it a simple to write and easy to maintain program. It has been said that a program written in C will pay a premium of a 50 to 100% increase in runtime, because no language is as compact or fast as Assembly Language. However, the time saved in coding can be tremendous, making it the most desirable language for many programming chores. In addition, since most programs spend 90 percent of their operating time in only 10 percent or less of the code, it is possible to write a program in C, then rewrite a small portion of the code in Assembly Language and approach the execution speed of the same program if it were written entirely in Assembly Language.
Approximately 75 percent of all new commercial programs introduced for the IBM PC have been written in C, and the percentage is probably growing. Apple Macintosh system software was formerly written in Pascal, but is now almost always written in C. The entire Applix 1616 operating system is written in C, with some assembler routines.