• C is a programming language developed at AT & T’s Bell Laboratories of USA . In 1972
it was designed and written by a man named Dennis Ritchie. In the late Seventies C
began to replace the more familiar languages of that time like PLALGOL, etc.
• It was initially designed for programming UNIX Operating system. Now the software
tool as well as the C compiler is written in C.
• Learning C is similar and easier .
• Instead of straight-away learning how to write programs, we must first 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.
• A computer program is just a collection of the instructions necessary to solve a specific
problem.
• The basic operations of a computer system form what is known as the computer’s
instruction set. And the approach or method that is used to solve the problem is known as
an algorithm.
• So for as programming language concern these are of two types.
1) Low level language
2) High level language
Low level language: Low level languages are machine level and assembly level language. In
machine level language computer only understand digital numbers i.e. in the form of 0 and 1.
High level language: These languages are machine independent, means it is portable. The
language in this category is Pascal, Cobol, Fortran etc. High level languages are understood by
the machine.
Three types of translator are there:
• Compiler
, • Interpreter
• Assembler
Compiler and interpreter are used to convert the high level language into machine
level language. The program written in high level language is known as source program and the
corresponding machine level language program is called as object program. Both compiler and
interpreter perform the same task but there working is different. Compiler read the program at-a-
time and searches the error and lists them. If the program is error free then it is converted into
object program. When program size is large then compiler is preferred. Whereas interpreter read
only one line of the source code and convert it to object code. If it check error, statement by
statement and hence of take more time.
Integrated Development Environments (IDE)
The process of editing, compiling, running, and debugging programs is often managed by a
single integrated application known as an Integrated Development Environment, or IDE for
short.
Structure of C Language program
1 ) Comment line
2) Preprocessor directive
3 ) Global variable declaration
4) main function( )
{