Secure String Handling in Windows Applications

// StringCopy.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <atlstr.h>
#define MAX_CHAR 255
#define BUFSIZE 85
#include <strsafe.h>

int _tmain(int argc, _TCHAR* argv[])
{

  /* declare unsafe copy variable */
  wchar_t unsafe_copy_str1[]=L"Hello world";
  wchar_t unsafe_copy_str2[MAX_CHAR];

  /* demo unsafe wcscpy without buffer check */
  wprintf(L"#### String Copy demo using wcscpy #### \n");
  wcscpy (unsafe_copy_str2, unsafe_copy_str1);
  wprintf (L"After copy string = %s\n\n", unsafe_copy_str2);
   
 	
  /* declare safe CRT variable */
  wchar_t safe_copy_str1[]=L"Hello world";
  wchar_t safe_copy_str2[MAX_CHAR];

  /* demo safe CRT variable */
  wprintf(L"#### String Copy demo using wcscpy_s #### \n");
  wcscpy_s( safe_copy_str2, _countof(safe_copy_str1),safe_copy_str1 );
  wprintf (L"After copy string = %s\n\n", safe_copy_str2);


  /* declare strsafe variable */
  wchar_t safe_copy_str3[]=L"Hello world";
  wchar_t safe_copy_str4[MAX_CHAR];

  /* demo strsafe variable */
   wprintf(L"#### String Copy demo using StringCchCopy #### \n");
    HRESULT Res;
    Res=StringCchCopy(STRSAFE_LPWSTR(safe_copy_str4), sizeof(safe_copy_str4), STRSAFE_LPWSTR(safe_copy_str3));
    if (Res != S_OK) {
      wprintf(L"StringCbCopy Failed: %s\n", safe_copy_str4);
      exit(-1);
   }

	wprintf (L"After copy string = %s\n\n", safe_copy_str4);


	return 0;
}