Below is the code to return the parent id of a process, given a process id.
This can be helpful in circumstances when we have to scan all the running processes to find out the spawned processes from another process.

[code language="cpp"]
// change this method signature according to your requirements
BOOL GetParentPID( DWORD dwParentId, DWORD &dwChildProcessId, bool &bChildProcess, std::list &listParentIds)
{
	OSVERSIONINFO  osver ;
	HINSTANCE      hInstLib ;
	HANDLE         hSnapShot ;
	BOOL           bContinue ;
	// ToolHelp Function Pointers.
	HANDLE (WINAPI *lpfCreateToolhelp32Snapshot)(DWORD,DWORD) ;
	BOOL (WINAPI *lpfProcess32First)(HANDLE,LPPROCESSENTRY32) ;
	BOOL (WINAPI *lpfProcess32Next)(HANDLE,LPPROCESSENTRY32) ;
	hInstLib = LoadLibraryA( "Kernel32.DLL" ) ;
	if( hInstLib == NULL )
	{
		return false;
	}
	// Get procedure addresses.
	lpfCreateToolhelp32Snapshot=
		(HANDLE(WINAPI *)(DWORD,DWORD))
		GetProcAddress( hInstLib,
		"CreateToolhelp32Snapshot" ) ;
	lpfProcess32First=
		(BOOL(WINAPI *)(HANDLE,LPPROCESSENTRY32))
		GetProcAddress( hInstLib, "Process32First" ) ;
	lpfProcess32Next=
		(BOOL(WINAPI *)(HANDLE,LPPROCESSENTRY32))
		GetProcAddress( hInstLib, "Process32Next" ) ;
	if( lpfProcess32Next == NULL ||
		lpfProcess32First == NULL ||
		lpfCreateToolhelp32Snapshot == NULL )
	{
		FreeLibrary( hInstLib ) ;
		return false ;
	}
	// Get a handle to a Toolhelp snapshot of the systems
	// processes.
	hSnapShot = lpfCreateToolhelp32Snapshot(
		TH32CS_SNAPPROCESS, 0 ) ;
	if( hSnapShot == INVALID_HANDLE_VALUE )
	{
		FreeLibrary( hInstLib ) ;
		return false ;
	}
	PROCESSENTRY32 procentry;
	// Get the first process' information.
	memset((LPVOID)&procentry,0,sizeof(PROCESSENTRY32));
	procentry.dwSize = sizeof(PROCESSENTRY32) ;
	bContinue = lpfProcess32First( hSnapShot, &procentry ) ;
	DWORD pid = 0;
	// While there are processes, keep looping.
	DWORD  crtpid= dwParentId;
	while( bContinue )
	{
		if(procentry.th32ParentProcessID == dwParentId)
		{
			// add the ids of the processes with the parent id
			listParentIds.push_back(procentry.th32ProcessID);
		}
		procentry.dwSize = sizeof(PROCESSENTRY32) ;
		bContinue = lpfProcess32Next( hSnapShot, &procentry );
	}//while ends
	// Free the library.
	FreeLibrary( hInstLib ) ;
	return true;
}
[/code]