C / C++ / MFC

Rajesh R Subramanian wrote:

GMP BigNum library[^] is your best bet perhaps.

trioum wrote:

storing the largest number

trioum wrote:

is there any data type is which I can store the 1 billion digit numbe

Mark Salsbery
Microsoft MVP - Visual C++

Mark Salsbery wrote:

Assuming you only need to work with digits 0-9, you only need
four bits per digit. That means two digits will fit in a byte.

Write a class to wrap a 500000000 byte array and cross your fingers
that you are actually able to allocate that much in one chunk.

CPallini wrote:

Now I need an array of the above class instances. The array should have 1 billion elements...

Mark Salsbery
Microsoft MVP - Visual C++

ganralf wrote:

do you mean I have to replace BSTR by _bstr_t ?

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

returned_string = ReturnString2Vb();

wprintf( L"%s\n", returned_string);

printf("%s\n", (const char *) returned_string);

return 0;
}

SysFreeString(returned_string);

ganralf wrote:

f I try to use the same function in a C++ project it returns garbage !

Takes an ANSI string as input, and returns a BSTR that contains an ANSI string. Does not perform any ANSI-to-Unicode translation.

--Mike--
Visual C++ MVP
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BSTR __stdcall ReturnString2Vb(void)
{
	return SysAllocString(L"This is a test string.");
}

Private Declare Function ReturnString2Vb Lib "C:\testdll.dll" () As String

Function ReturnString() as string
	Dim returned_string As String
	
	returned_string = ReturnString2Vb()
end function