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Basics

1. What is C language?​

The C programming language is a standardized programming language developed in the early 1970s by Ken Thompson and Dennis Ritchie for use on the UNIX operating system. It has since spread to many other operating systems, and is one of the most widely used programming languages. C is prized for its efficiency, and is the most popular programming language for writing system software, though it is also used for writing applications.

2. What are the Facts about C ?​

  1. C was invented to write an operating system called UNIX.
  2. C is a successor of B language which was introduced around 1970
  3. The language was formalized in 1988 by the American National Standard Institute (ANSI).
  4. By 1973 UNIX OS almost totally written in C.
  5. Today C is the most widely used System Programming Language.
  6. Most of the state of the art software have been implemented using C

3. What are the Advantages of C ?​

The good news about C is that you can write code which runs quickly, and your program is very "close to the hardware". By that I mean that you can access low level facilities in your computer quite easily, without the compiler or run time system stopping you from doing something potentially dangerous.

  • Source code portability : C code can be compiled and used in any Operating System e.g. Unix, Windows etc.
  • The ability to operate "close to the machine"
  • Efficiency and fast

4. What Comprises a C Program?​

A program is the thing that you write to perform a particular task. It will actually be a file of text, often called a source file. This is what the compiler acts on. A source file contains three things :

  • instructions to the compiler
  • information about the structures which will hold the data to be stored and manipulated.
  • instructions which manipulate the data.

5. Why to use C ?​

C was initially used for system development work, in particular the programs that make-up the operating system. C was adoped as a system development language because it produces code that runs nearly as fast as code written in assembly language. Some examples of the use of C might be:

  • Operating Systems
  • Language Compilers
  • Assemblers
  • Text Editors
  • Print Spoolers
  • Network Drivers
  • Modern Programs
  • Data Bases
  • Language Interpreters
  • Utilities

6. What are Steps in Learning C ?​

Learning English language and learning C language both are similar. Learning English is to first learn the alphabets then learn to combine these alphabets to form words, which in turn are combined to form sentences and sentences are combined to form paragraphs. Learning C is similar. To write programs, we must know what alphabets, numbers and special symbols are used in C, then how using them constants, variables and keywords are constructed, and finally how are these combined to form an instruction. A group of instructions would be combined later on to form a program.

7. What is C Character Set ?​

A character denotes any alphabet, digit or special symbol used to represent information. Below Fig shows the valid alphabets, numbers and special symbols allowed in C.

  • Alphabets : A, a, B, b …. Z, z
  • Digits: 1, 2, 3,4,5,6,7,8,9,0
  • Special Characters: ~, !, @, #, %, ^, &, *, (,), _