What is computer?
Computer is an electronic device that takes input, process
it and gives output.
Examples are desktop computers, Laptop, Palmtop, Super
computer, embedded systems, etc.
Is computer really
works on 0 and 1?
There is no physical significance of 0 and 1 in computer
system. 0 and 1 are just representation of two states of voltage levels in
digital circuits. If there is a supply of high volt in the circuit it is termed
as 1 and for low volt it is 0.
These encoding help us to handle any sort of information
through digital circuits.
What is Hardware?
Hardware is a
comprehensive term for all of the physical parts of a computer, as
distinguished from the data it contains or operates on, and the software that provides
instructions for the hardware to accomplish tasks.
What is file?
A computer file is a
data bundle created by a program used to refer back to saved work or support
the operating of the program.
Files are of
different types, which mean information is encoded in a particular manner. Each
such manner is a separate file format. Notice files stored in your computer’s
memory disk, each has some name for identification followed by file extension.
File name and extension are separated by a dot operator. File extension tells about
type of the file. For example track1.mp3 is a file with extension mp3 which
means it is an audio file.
Among the several
file formats, we are concern about a special file format with extension exe.
These files are called executable files.
For beginners of C
language should understand the purpose of learning programming language.
Softwares are programs (or a collection of programs) developed by writing
instructions (that need to be executed during execution) in certain programming
language. C language is just one of them.
When we say we are going to develop software through C
language, it means you are attempting to create an exe file. In loose terms, we
can say an exe file is your software.
So the abstract is, you are here to write code in C language
which then converted in to an exe file.
You can deliver this exe file to your client. He can enjoy
your software without seeing your code. In the later segment you would
understand why he can’t see your programming code.
What is program and
process?
Program is a set of instruction to perform a particular
task.
Active state of a program is called process.
What is an operating
system?
Operating system is
essential software which provides an interface between user and machine. It acts
as a manager in the system, which manages hardware and software resources. It
also does process management, memory management and file management.
Basic Computer
architecture
Operating system allocates memory for our program in RAM.
First instruction goes to the processor and resides in instruction register.
This instruction is decoded by control unit. Control unit sends appropriate
signal to ALU. ALU performs specific task.
Registers, control unit and Arithmetic Logic Unit are part
of processor. ALU is responsible to perform all kind of arithmetic, logical and
shift instructions.
Again next instruction moves to processor and stored at
instruction register, control unit decode it and sends a signal to ALU. Every
instruction of the program executes in similar fashion in a sequential manner.
As soon as the last instruction is executed memory of the
program will released from RAM.
Why Languages?
Executable files are machine code which is operating system
dependent and hardware dependent. To create such file we need to know about
hardware specifications and OS policies. This increases extra learning overhead
to the programmer. One easy solution is to learn a simple hardware independent
coding language like C.
Once you learn C language you can write code (known as
source code) and save it as a source file. This code is not readable for
machine. You need to convert it into machine code. A software known as compiler
is used as a translator, which translates your source code in to object code.
Object files containing machine code are not sufficient to
understand by computer, you need to link this code with predefined code stored
in library files. This can be done with the help of software called linker.
Linker generates an executable file.
History of C language
l C
language was developed by Dennis Ritchie in 1972 at AT & T’s Bell Labs, New
Jersy, USA .
l C
language is inspired from B language which was developed by Ken Thompson.
l80%
code of UNIX operating system is written in C language.
l C
is a middle level language that is a combination of high level and low level
language.
l C
follows procedure oriented programming approach.
l C
follows top down approach.
IDE for C
An IDE normally consist of:
l A
source code editor
l Compiler
or interpreter
l Build
automation
l A
debugger
There are n numbers of IDEs available for C. They are specific to operating system. These IDEs not only gives you facility to write and edit code but also provide facility to compile and link to create object file and executable file.
Technical terminologies:
Compile: It is a process of compiling your source code and
producing object code
Debug: It is an activity to remove errors in your source code.
Errors are called bugs.
Error: Errors are categorized as syntax error(compile time error),
Linker error, Run time error, Logical error. These are mistakes in your program
which needs to be handled
Run: When you run your
program it means execution of your program.
Syntax: Grammar for computer language
Turbo: Software (IDE) developed by Borland Inc.
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