Introduction to C language

It is mandatory to have idea about certain fundamentals before starting up with C language and programming in C language.

What is a program?

Simply, a program is a set of instructions.

When this program (high-level code*) is “compiled”, it produces executable file (low-level or machine code*). All the software that we use in our daily life are executable files.

*Humans stand “higher” than machines. Hence, the code developed by humans is high-level code and that developed by machines is low-level code.

A compiler converts high-level code to low-level code. There are huge number of compilers. Eg: AMPC, Turbo C, GCC, Keil C, Micro C, Open64, THINK C, etc.

Out of all the compilers, GCC is commonly used, as the LINUX OS is developed using C language along with GCC compiler.

The term application development deals with three difference levels, as shown below.

 

Levels of programming

Throughout this blog, we deal with developing applications using C language.

Also, it is very necessary to differentiate the terms Program, Application and Process. A program is the code that is coded by the developer. An application is the executable file generated, after executing the program. A process is the instance of application in the RAM, when the application is serving the purpose to the user.