Why is it difrent but when I check its the same?

**Benzakhar** · 12-12-2003

refer to these 2 pieces of code
<1>
h[0] = (OLECHAR) 72;
h[1] = (OLECHAR) 69;
h[2] = (OLECHAR)76;
h[3] = h[2];
h[4] = (OLECHAR) 111;
h[5] = NULL;

<2>
h[0] = (OLECHAR) "H";
h[1] = (OLECHAR) "E";
h[2] = (OLECHAR)"L";
h[3] = h[2];
h[4] = (OLECHAR) "o";
h[5] = NULL;

When I convert sample 1 to BSTR then send it to VB I get "HELLo" at the other end. When I convert sample 2 to BSTR then send it to vb. I get some thing like "????". And when I check "H" and 72 and the rest in C++ its the same. Why is it like that?

Thanx in advance!

**gcn_zelda** · 12-12-2003

Probably because VB is not as efficient as C++ and was created by Microsoft :P

**Benzakhar** · 12-12-2003

What company created C++?

Microsoft hides to many things. Once I started learning C++ I learned that Microsoft hides alot more things lol. But this is the strangest thing. In c++ (OLECHAR) 72 = (OLECHAR) "H" but in VB (OLECHAR) 72 = "H" and (OLECHAR) "H"= "?". It makes no sense? You can check if you want to.

STDMETHODIMP CTEST_ATL::get_Text(BSTR *pVal)
{
// TODO: Add your implementation code here
//OLECHAR *h;
OLECHAR *h = new OLECHAR[5];

h[0] = (OLECHAR) "H";
h[1] = (OLECHAR) "E";
h[2] = (OLECHAR)"L";
h[3] = h[2];
h[4] = (OLECHAR) "o";
h[5] = NULL;

SysFreeString(*pVal);
*pVal = SysAllocString(h);
//MessageBox(0,h,"caption",0);
//*pVal = (BSTR) h;
return S_OK;
}

Do that then create an ole dll. put something like stringvariable = Test_ATL.Text
msgbox s
and you get "????"
replace the characters in " " with its character code and you get what you want. Have a comparisan using if statements in C++ and its the same thing?

**Benzakhar** · 12-12-2003

I think I fiqured it out. Create a new win32 console project and add this to the main() function;

int i;
i = (int) 'H';
cout << i << '\n';
i = (int) "H";
cout << i;
cin >> i;
return 0;

it compares 'H' and "H". The results are difrent. Why is 'H' and "H" is difrent?

Thanx in advance!

**Fahrenheit** · 12-12-2003

'H' is the ASCII number of the letter H.
"H" is a string containing H and \0.

**XSquared** · 12-12-2003

>>"H" is a string containing H and \0.
And it will return a pointer to the location of the first character of the string in memory.

**Benzakhar** · 12-12-2003

If you would create a pointer and browse around "H" you would see it is difrent from 'H' and its more than 2 chars one H and the other NULL. If you would compile this;
char h;
h = "H";
you would recieve the error "Cannot convert char[2] to char". There it say's 2 thus its 3 bytes, there is char[0] char[1] and char[2] then there is more then a null - terminated string. Save it to a long variable for storage to browse around it.

char *i = new char;
long ii;
ii = (long) "H";
i = (char *) &ii;
cout << *i << '\n';
i++;
cout << *i << '\n';
i++;
cout << *i << '\n';
cout << ii << '\n';
cout << "H";
cin >> i;
here is something that browses around the "H". If you would take a look you would see that the first byte is a symbol the next is the letter p then a capitle B. and if you put cout << "H"; or cout << 'H'; its the same thing. The mysteries of strings.

**Codeplug** · 12-12-2003

What's a mystery to me is how 2 can equal 3.

gg

**anonytmouse** · 12-13-2003

An olechar is a unicode character so you could do something like this:

Code:

h[0] = L'H';
LPOLESTR myOleStr = L"Hello";
or
LPOLESTR myOleStr = OLESTR("Hello");
or
OLECHAR myOleStr[] = L"Hello";

Also, unless pVal is an [in,out] parameter you should not free its contents.

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