[Original] limit the number of times the software is used

In some cases, such as a trial version ~~ And so on ~~ In fact, it is mainly a trial version, which limits the number of users to use.

We generally write some identification values to the Registry to accomplish this goal ~

 

The following is the implementation code:

VC platform MFC framework

   1:  unsigned char buffer[255]={0}; 

   2:  unsigned long length; 

   3:  unsigned long type; 

   4:  HKEY hKey; 

   5:   

   6:  RegOpenKey(HKEY_LOCAL_MACHINE, 

   7:      "Software//Classes//CLSID//{79AD74E9-1C65-408B-9880-E7937DB5AA93}", &hKey); 

   8:  RegQueryValueEx(hKey,"Num",NULL,&type,buffer,&length); 

   9:  RegCloseKey(hKey); 

  10:   

  11:  int Count; 

  12:  Count = atoi((const char*)buffer); 

  13:  if(Count == 0) 

  14:  { 

15: afxmessagebox ("this software is a trial version and can be used only five times ");

  16:      RegCreateKey(HKEY_LOCAL_MACHINE, 

  17:          "Software//Classes//CLSID//{79AD74E9-1C65-408B-9880-E7937DB5AA93}",&hKey); 

  18:      RegSetValueEx(hKey,"Num",0,REG_SZ,(const unsigned char *)"5",strlen("5")); 

  19:      RegCloseKey(hKey); 

  20:  } 

  21:  else if(Count == 1) 

  22:  { 

23: afxmessagebox ("full usage", mb_ OK, 1 );

  24:      exit(1); 

  25:  } 

  26:  else 

  27:  { 

  28:      char buf[255]={0}; 

  29:      Count -= 1; 

  30:      itoa(Count,buf,10); 

  31:      CString str; 

  32:      RegOpenKey(HKEY_LOCAL_MACHINE, 

  33:          "Software//Classes//CLSID//{79AD74E9-1C65-408B-9880-E7937DB5AA93}",&hKey); 

  34:      RegSetValueEx(hKey,"Num",0,REG_SZ,(const unsigned char*)buf,strlen(buf)); 

  35:      RegCloseKey(hKey); 

  36:  }    

 

The above ~~~

However, this method is easy to crack. It's okay to use the trial versions that are not very important .~~~