C / C++ / MFC

Stefan63 wrote:

If you want to, you can replace the system's operator new and delete with your own implementations. These could then store additional information, such as the number of elements being allocated...

class Buffer {
	public:
		Buffer(unsigned nSize) : m_pBuffer(NULL), m_nLength(nSize) {
			if (nSize > 0) {
				m_pBuffer = new BYTE[nSize];
				if (m_pBuffer == NULL) {
					m_nLength = 0;
					//you ran out of memory, do something
				}
			}
		}
		~Buffer() {
			if (m_pBuffer != NULL) {
				delete []m_pBuffer;
			}
		}
		unsigned GetLength() {
			return m_nLength;
		}
		BYTE &operator[](unsigned nIndex) {
			if (nIndex >= m_nLength) {
				//error somehow
			}
			return m_pBuffer[nIndex];
		}
		BYTE *operator*() {
			return m_pBuffer;
		}

	private:
		BYTE *m_pBuffer;
		unsigned nLength;
};

Buffer bufData(64);
strcpy(*bufData, "hello world"); //the operator*() can be used to get a pointer to the data
//print the length
printf("The valid range is 0-%u\n", bufData.GetLength() - 1); //remember indices start at 0 and go to n-1
printf("The 2nd character is \'%c\'\n", bufData[1]); //Again, indices start at 0 making the 2nd element index 1
//The buffer automatically cleans up its memory when it goes out of scope

#define _countof(array) (sizeof(array)/sizeof(array[0]))

goldenrose9 wrote:

how to get the upper bound and lower bound of an array

BYTE *pByte = new BYTE[64];

PathCompactPath(pDC->GetSafeHdc(),strMPGFilePath.GetBuffer(MAX_PATH),oRc.Width());
strMPGFilePath.ReleaseBuffer();

MsmVc wrote:

I try to run dos command through mfc vc++.

#include <windows.h>
#include <stdio.h>

char * ExecuteCMD(char * command)
{
		SECURITY_ATTRIBUTES sec;
		PROCESS_INFORMATION pi;
        STARTUPINFO si;
		HANDLE hOutR, hOutW;
		DWORD BTAvail;
		char * Result = NULL;
		char * cmdline = NULL;
		char cmdpath[256];
		OSVERSIONINFO OSVersionInfo;
		DWORD Read = 0;

			ZeroMemory(&pi, sizeof(PROCESS_INFORMATION));
			ZeroMemory(&sec, sizeof(SECURITY_ATTRIBUTES));
			sec.nLength = sizeof(SECURITY_ATTRIBUTES);
			sec.bInheritHandle = TRUE;
			sec.lpSecurityDescriptor = NULL;
	
	if (CreatePipe(&hOutR, &hOutW, &sec, 0)) 
	{
				ZeroMemory(&si, sizeof(STARTUPINFO));
				si.cb = sizeof(STARTUPINFO);
				si.hStdOutput = hOutW;
				si.dwFlags = STARTF_USESTDHANDLES|STARTF_USESHOWWINDOW;

			cmdline = (char *) GlobalAlloc(GMEM_FIXED, (7 + lstrlen(command)));
			lstrcat(lstrcpy(cmdline, " /a /c "), command);

			OSVersionInfo.dwOSVersionInfoSize = sizeof (OSVERSIONINFO);
			GetVersionEx (&OSVersionInfo);

			if (OSVersionInfo.dwPlatformId == VER_PLATFORM_WIN32_NT)
			{
				GetEnvironmentVariable("ComSpec", cmdpath, 2048);
			}

		if (CreateProcess(cmdpath, cmdline, &sec, &sec, TRUE, NORMAL_PRIORITY_CLASS, NULL, NULL, &si, &pi))
		{
			WaitForSingleObject(pi.hProcess, INFINITE);
			CloseHandle(pi.hThread);
			CloseHandle(pi.hProcess);
			PeekNamedPipe (hOutR, NULL, 0, NULL, &BTAvail, NULL);
				if (BTAvail > 0)
				{
					Result = (char *) GlobalAlloc(GMEM_FIXED, BTAvail + 1);
					ReadFile(hOutR, Result, BTAvail, &Read, NULL);
					Result[BTAvail] = '\0';
					OemToChar(Result, Result);
					return Result;
				}
		}
}
	return NULL;
}

int main(int argc, char **argv)
{
	char *cmd = ExecuteCMD("dir");
	puts(cmd);
}

typedef std::vector<std::string>   WidgetIds;    
typedef std::map<std::string, int> WidgetPrices;