C / C++ / MFC

7-Jun-08 3:28

how can i add two integers(numbers) without using + operator,rather by doing bit manupolation???

Michael Schubert7-Jun-08 3:35

Michael Schubert

7-Jun-08 3:35

May I ask why you want to do that?

MahaKh7-Jun-08 4:07

7-Jun-08 4:07

its my university assignment, in which we have to add 2 numbers but without + operator, can u help me in this?

Michael Schubert7-Jun-08 4:10

Michael Schubert

7-Jun-08 4:10

In that case you should really do it yourself! You don't want to be caught cheating, do you?

MahaKh7-Jun-08 4:36

7-Jun-08 4:36

yeah! but we really haven'nt been taught abt it...i m working abt it, if u dont wana help out then its ok.
thnx

CPallini7-Jun-08 4:58

CPallini

7-Jun-08 4:58

Well it is not difficult to adapt the standard operation you do on paper with base-10 numbers to a base-2 system.
Smile | :)

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rp_suman7-Jun-08 5:44

rp_suman

7-Jun-08 5:44

You can do this like, have two integers and a result integer.

For each input integer, check its bits from right to left(least significant bit to most)

If the bit value is one and same bit of resulting integer is zero, make resulting integer's bit to one.

If both are one then keep this bit's position, check which bit on left side of resulting integer value is zero, make it one and make other bits on right side until above kept position to zero.
Need to do for each integer input.

The process could be something like this or more easier, think yourself..

Thanks,
Suman

--
"Programming is an art that fights back!"

MahaKh7-Jun-08 10:37

7-Jun-08 10:37

thanks a lot

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C^hris L^osinger7-Jun-08 5:45

C^hris L^osinger

7-Jun-08 5:45

the algorithm for this is very short: basically, four operations in a loop.

some key points to think about:

if the binary representation of the two numbers you are adding do not have any 1 bits in common, addition is equivalent to a simple OR. 0x01 | 0x02 = 0x03, 0x08 | 0x03 = 0x0b (8 + 3 = 11 = 1000b + 0011b = 1011b). but, such a situation is the exception.

so, what do you do when numbers share bits?

(1 + 1 = 2)
0001b
0001b +
----------
0010b

(3 + 3 = 6)
0011b
0011b +
----------
0110b

(9 + 3 = 12)
1001b
0011b +
----------
1100b

see the pattern ?

1 + 1 = 2 but there is no 2 in base2, so put a zero, carry the one to the next column and do it again.

Clearing client window

Kwanalouie7-Jun-08 2:15

Kwanalouie

7-Jun-08 2:15

Using Visual C++ 6.0 MFC in SDI application

Under certain conditions I want my OnDraw routine to display a blank window, instead of what was previously drawn there. When I use the InvalidateRect(0) function, the OnDraw gets called, but I am looking for some window function that will clear everything. How do I do that?
Thanks

Nelek7-Jun-08 2:19

7-Jun-08 2:19

Why don't you put a flag in your OnDraw ()?

OnDraw ()
{
    if (bBlank)  //Nothing has to be drawn
      return;

    Your Drawing code...
}

and bBlank = TRUE or FALSE as you need the blank window or not

Regards.
--------
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Kwanalouie7-Jun-08 3:15

Kwanalouie

7-Jun-08 3:15

The problem was that I would set a flag for my OnDraw routine to do as you suggested, but in the function that set that flag I simply did

flag = NOTDRAW;
Invalidate(0);

When I did this, with the OnDraw routine simply returning when it saw that flag, the old info in the client window would not be erased.

When I changed things to

Invalidate(0);
flag = NOTDRAW;
Invalidate(0);

in the function that set the flag, then the old info in the client window would get erased. So I'm confused as to what is happening with the Invalidate(0) function.

Nelek7-Jun-08 3:23

7-Jun-08 3:23

I am not sure why it happens. I usually use the Invalidate () without 0 and just afterwards an UpdateWindow (). It is supposed that Invalidate triggers the update, but I got used to that when I start coding in MFC because of some tutorials I used. The only problem with this is that depending on how much info is on the screen it can make it flick a bit.

Regards.
--------
M.D.V. Wink | ;)

Is it possible to create C++ obj in C with new operator?

Ravi Bhavnani7-Jun-08 11:27

Ravi Bhavnani

7-Jun-08 11:27

Kwanalouie wrote:
I am looking for some window function that will clear everything

Write a handler for WM_ERASEBKGND[^]

/ravi

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Nandu_77b7-Jun-08 0:52

Nandu_77b

7-Jun-08 0:52

I have a doubt whether it is possible to creat a C++ object in C with new operator. As show below?

//////////////////////////ExmCPP.cpp///////////////////////////////////////
class TDM_API
{
public:
TDM_API();
~TDM_API();
int WriteIntoLog(const string sStr);
}

////////////////////ExampleC.c File/////////////////////////////////////
#ifdef __cplusplus
extern "C" {
#endif

DLLEXPORT int td_init()
{
TDM_API* td = new TDM_API();
m_nHandle = (int) td;

td->WriteIntoLog("This is for test");

return (int) m_nHandle;
}

Re: Is it possible to create C++ obj in C with new operator?

Gary R. Wheeler7-Jun-08 0:58

Re: Is it possible to create C++ obj in C with new operator?

7-Jun-08 0:58

By default, Visual Studio will compile ExampleC.c as a C program, and will signal an error on the new operator. You can set a compile option to compile it as C++, which eliminates the error.

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Nandu_77b7-Jun-08 1:22

Nandu_77b

7-Jun-08 1:22

can you please guide me to change the compailer option in VS 6.0.

Thanks,
Nandu

Re: Is it possible to create C++ obj in C with new operator?

Gary R. Wheeler7-Jun-08 2:52

Re: Is it possible to create C++ obj in C with new operator?

7-Jun-08 2:52

Hmmm. I just started up VC6. It doesn't have an option for compiling a .C source file as C++. This option must have come later, in Visual Studio .NET or 2003.

You may have to rename your .C file to .CPP in order to get VC6 to compile it as C++.

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Nandu_77b7-Jun-08 3:22

Nandu_77b

7-Jun-08 3:22

Thanks, the above solution solved my problem.

Esc Button use for Close the Dialog Box.

Le@rner7-Jun-08 0:41

Le@rner

7-Jun-08 0:41

Hi all,

Esc Button use for Close the Dialog Box.i want to remove the funcnality how can i do this.

Thanks in advance.

IN A DAY, WHEN YOU DON'T COME ACROSS ANY PROBLEMS - YOU CAN BE SURE THAT YOU ARE TRAVELLING IN A WRONG PATH

Gary R. Wheeler7-Jun-08 1:05

7-Jun-08 1:05

If you are using MFC, add an OnCancel() handler to your CDialog-derived class.

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Nelek7-Jun-08 2:13

7-Jun-08 2:13

He wants to remove the OnCancel, not to call it :P

Regards.
--------
M.D.V. Wink | ;)

Gary R. Wheeler7-Jun-08 2:18

7-Jun-08 2:18

It sounded like he wanted to prevent the ESC key from closing the dialog. To do that in an MFC application with a CDialog-derived dialog class, you add an empty OnCancel member function.

You can't "remove" OnCancel in any case. The CDialog window procedure is going to call it, either in your class or the base class.

Software Zen: delete this;
Fold With Us![^]

Nelek7-Jun-08 2:22