UNIT 2 : INTRODUCTION

We have seen many software applications like, word processor, game applications, web browsers, facebook etc.

All these are developed using some of the programming languages like C, C++, Java, Visual C#.Net, Python and there are so many other languages are out there.

Programmers use those languages to create instructions which would be given to the computer ad then the computer would execute them .
And that’s how those softwares we use do work. 
I have given the idea behind application development in very simpler words.

So here, we are going to learn the programming language C. 

Before creating the big applications, we should know the basics of the language like, how to use them, in other words, the grammar of the language.

Initially, we are not going to create the applications with colorful interfaces but, the simpler ones with command prompt. 

To start with programming, we should know the ingredients we need;

C editor :

All the C programs must be written in C editor. 

It would be something like a text editor or a specialized version of a text editor for C language. 

Once we type the program, we need to save the program as a c file that is .c extension

And now, this will be the source program or known as source code.

e.g : text editor, notepad++, etc.

C compiler

The source code should be compiled using a compiler. 

That is, the compiler would check if the program is error free. 

If there is any error, it would highlight that and the programmer has to correct those errors.

A program cannot run if there is any error

Once the program is errorfree, the the compilation would be success and it produce the Object code.

That is the compiler would convert the source program into its equivalent computer language,usually a machine code language (i.e., binary) or an intermediate language such as RTL.

The object code file contains a sequence of instructions that the processor can understand but that is difficult for a human to read or modify. 

For this reason and because even debugged programs often need some later enhancement, the source code is the most permanent form of the program.

When you purchase or receive operating system or application software, it is usually in the form of compiled object code and the source code is not included. 

Once the executable object code is ready, the program can be run

e.g : (Borland) Turbo C, Visual C++ Express, etc

Though not absolutely needed, many programmers prefer and recommend using an Integrated development environment (IDE) instead of a text editor. 

An IDE is a suite of programs that developers need, combined into one convenient package, usually with a graphical user interface. 

These programs include a text editor, linker, project management and sometimes bundled with a compiler. 

They also typically include a debugger, a tool that will preserve your C source code after compilation and enable you to do such things as step through it manually, or alter data as an aid to finding and correcting programming errors.

e.g : Dev C++ , Microsoft Visual Studio Express , CodeLite , Code::Blocks , Netbeans, Eclipse CDT

For beginners it is recommended not to use an IDE, since it hides most of what is going on. 

Using the command line builds up familiarity with the tool-chain. 

An IDE may be useful to somebody with programming experience but knows how the IDE works. 

So as a general guideline: Do not use an IDE unless you know what the IDE does!

Knowledge about C:

The rules, syntax, keywords and how they must be used to write the code (instructions), how to make the program in a simpler and efficient ways. 

These are are all very essential for the programming. 

we will learn them here , step by step.