C / C++ / MFC Discussion Boards

Re: Algorithm Problem(C++ solution)

OriginalGriff12-Jul-19 5:10

OriginalGriff

12-Jul-19 5:10

When you posted this yesterday in QA: How to solve this problem[^]
You posted it together with two very different code fragments "you wrote" but couldn't get working, and were encouraged to use the debugger to fix them.

Now, you're posting the question again with no code and asking for an algorithm "to solve it".

We are more than willing to help those that are stuck: but that doesn't mean that we are here to do it all for you! We can't do all the work, you are either getting paid for this, or it's part of your grades and it wouldn't be at all fair for us to do it all for you.

So we need you to do the work, and we will help you when you get stuck. That doesn't mean we will give you a step by step solution you can hand in!
Start by explaining where you are at the moment, and what the next step in the process is. Then tell us what you have tried to get that next step working, and what happened when you did.
And please, don't tell us you "wrote the code" because it's pretty clear from yesterday's post that you found something on the internet and hoped it would magically meet all your homework criteria...

Sent from my Amstrad PC 1640
Never throw anything away, Griff
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Re: Algorithm Problem(C++ solution)

Joe Woodbury12-Jul-19 10:02

Joe Woodbury

12-Jul-19 10:02

There's a pun somewhere in all of this, solve it!

Re: Algorithm Problem(C++ solution)

Stefan_Lang15-Jul-19 2:05

Stefan_Lang

15-Jul-19 2:05

- where are the planes at the start: somewhere at the airport, at a runway, or in the air?

- what are the times when planes are scheduled to arrive or take off? If not times, what is the order? If not order, is there any other restriction about the sequence?

- what does delay(?) time mean for a plane? Is it the maximum time it can wait at the airport, or remain in the air? If so, when does the time start counting? Or does that time only start ticking when on a runway?

- what does delay(?) time mean for a runway? What is it's effect? When does it start?

- what do you mean by runway capacity? Typically I'd say the capacity of any runway is exactly 1, as there can't be two planes on the same runway at the same time! But clearly you mean something else. Explain!

- the goal is to optimize a time for the airport - which time is that?

GOTOs are a bit like wire coat hangers: they tend to breed in the darkness, such that where there once were few, eventually there are many, and the program's architecture collapses beneath them. (Fran Poretto)

Re: Algorithm Problem(C++ solution)

Gerry Schmitz15-Jul-19 8:14

Gerry Schmitz

15-Jul-19 8:14

Do you work for Boeing?

The Master said, 'Am I indeed possessed of knowledge? I am not knowing. But if a mean person, who appears quite empty-like, ask anything of me, I set it forth from one end to the other, and exhaust it.'
― Confucian Analects

Overflow check on integer multiplication in C ?

Hans9999-Jul-19 2:01

Hans999

9-Jul-19 2:01

Hello,

I need to multiply integer value with a factor and want to do an overflow check with INT_MAX, INT_MIN for this.

Integer contains 4 bytes on my machine an this is the max variable-size.
I need to do this check for signed integer and unsigned integer. Only integer math/variables allowed.

The factor always comes as fraction with a nominator and denominator. The denominator always is 10
Factor might be greater 1 or less than 1

So for example fraction is 25/10, varible a is signed integer

a = (a * 25)/10 -> may cause overflow, because (a * 25) can be > INT_MAX ( or < INT_MIN )

Overflow checks:
if (a > (INT_MAX * 10)/25 -> not possible because of overflow, INT_MAX is the maximum number the compiler can store.
if (a > INT_MAX * (10/25) -> not possible because 10/25 is 0.4 which will be 0 in integer math.

So any idea how to solve my problem?

Thanks for any hint!

Re: Overflow check on integer multiplication in C ?

Daniel Pfeffer9-Jul-19 3:10

Daniel Pfeffer

9-Jul-19 3:10

One way would be to perform the multiplication as a double-precision operation, and then examine the high word. For unsigned values (in pseudocode):

// HI_HALF - returns the upper N/2 bits of an N-bit integer
// LO_HALF - returns the lower N/2 bits of an N-bit integer
// MAKE_DIGIT - combines two N/2-bit values to make an N-bit integer

// multiply a DIGIT a by a DIGIT b, returning a two-DIGIT result
// a, b must be unsigned

DIGIT alow = LO_HALF(a)
DIGIT ahigh = HI_HALF(a)
DIGIT blow = LO_HALF(b)
DIGIT bhigh = HI_HALF(b)
DIGIT carry
DIGIT accumulator
DIGIT result[4]

accumulator = alow * blow
carry = HI_HALF(accumulator)
result[0] = LO_HALF(accumulator)

accumulator = alow * bhigh + carry
result[1] = LO_HALF(accumulator)
result[2] = HI_HALF(accumulator)

accumulator = ahigh * blow + result[1]
result[1] = LO_HALF(accumulator)
carry = HI_HALF(accumulator)

accumulator = ahigh * bhigh + result[2] + carry
result[2] = LO_HALF(accumulator)
result[3] = HI_HALF(accumulator)

// combine result[3] and result[2] into 1 DIGIT
// combine result[1] and result[0] into 1 DIGIT
return MAKE_DIGIT(result[3], result[2]), MAKE_DIGIT(result[1], result[0])

Note that many optimizations may be performed on the above code; it is laid out like this for easy comprehension.

For the operation a * b, if the high digit is non-zero, the result has overflowed
For the operation a * b / c, if the high DIGIT of (a * b) >= c, then the entire operation will overflow.

Signed values are left as an exercise for the student.

Freedom is the freedom to say that two plus two make four. If that is granted, all else follows.
-- 6079 Smith W.

Re: Overflow check on integer multiplication in C ?

Joe Woodbury9-Jul-19 7:41

Joe Woodbury

9-Jul-19 7:41

All that matters is if a * factor overflows, so the /10 can be ignored. I believe you just need to check if (a <= (INTMAX / factor)).

Re: Overflow check on integer multiplication in C ?

leon de boer10-Jul-19 3:35

leon de boer

10-Jul-19 3:35

It will take more effort and cpu cycles to pick off the overflow than simply move it to next size up integer, do the mult on a that type and look at the result for overflow
So for 16 bit int and 32bit long as an example

long b = a;
b *=25
b /=10
if (b & 0x7FFF0000 != 0) 
{
     // error result in b is larger than an int
}
a = (int) b;

If you want to do it proper anal uses standard ints

#include <stdint.h>
int16_t a = ????;
int32_t b = a;
b *=25
b /=10
if (b & 0x7FFF0000 != 0) 
{
     // error result in b is larger than an int
}
a = (int16_t) b;

In vino veritas

modified 10-Jul-19 9:41am.

Re: Overflow check on integer multiplication in C ?

CPallini10-Jul-19 4:57

CPallini

10-Jul-19 4:57

Nice.

I have created a Wrapper but while calling a function from C# its moving to my Lib file and giving below error andy solution?

Member 143147593-Jul-19 22:14

Member 14314759

3-Jul-19 22:14

hi I m getting this error any suggestion:

AccessibilityObject = 'object.AccessibilityObject' threw an exception of type 'System::Runtime::InteropServices::COMException^'

Re: I have created a Wrapper but while calling a function from C# its moving to my Lib file and giving below error andy solution?

leon de boer4-Jul-19 2:39

leon de boer

4-Jul-19 2:39

You don't have privilege to run it. Log in or run the program as administrator.

In vino veritas

"crosslinking " - different architecture libraries - is is possible?

Vaclav_1-Jul-19 10:54

Vaclav_

1-Jul-19 10:54

Update
I linked only part of the /lib folder , my mistake.

Still like to know if my original question - linking to network resource is feasible.
This is basically result of my inability to ".configure" for non - native architecture.
The "configure" kept asking for dependency after dependency.
So I ended up running .configure on required architecture.

After a detour I am back to tying to implement / crosscompile C++ code.
I can option a prefix for desired architecture , but still having an issue linking to specific desired architecture libraries.
I was unable to use ".configure " to create correct foreign architecture library on "local" architecture.

I did a hack by copying an entire "foreign" folder to local device and was partially successful linking to it.

Still missing some library and could do same hack.

Is there a more "elegant" way to accomplish that?

Here is what is still failing to link correctly.
Sorry for the mess.

gcc version 5.4.0 20160609 (Ubuntu/Linaro 5.4.0-6ubuntu1~16.04.9) 
COMPILER_PATH=/usr/lib/gcc-cross/arm-linux-gnueabihf/5/:/usr/lib/gcc-cross/arm-linux-gnueabihf/5/:/usr/lib/gcc-cross/arm-linux-gnueabihf/:/usr/lib/gcc-cross/arm-linux-gnueabihf/5/:/usr/lib/gcc-cross/arm-linux-gnueabihf/:/usr/lib/gcc-cross/arm-linux-gnueabihf/5/../../../../arm-linux-gnueabihf/bin/
LIBRARY_PATH=/usr/lib/gcc-cross/arm-linux-gnueabihf/5/:/usr/lib/gcc-cross/arm-linux-gnueabihf/5/../../../../arm-linux-gnueabihf/lib/../lib/:/lib/../lib/:/usr/lib/../lib/:/usr/lib/gcc-cross/arm-linux-gnueabihf/5/../../../../arm-linux-gnueabihf/lib/:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-L/media/z/KINGSTON/BULEZ_LIB_RPI' '-L/usr/arm-linux-gnueabihf/lib' '-L/media/z/DEV/BLUEZ/BLUEZ_LIB' '-v' '-o' 'VNAR_1971_JULY' '-shared-libgcc' '-march=armv7-a' '-mfloat-abi=hard' '-mfpu=vfpv3-d16' '-mthumb' '-mtls-dialect=gnu'
 /usr/lib/gcc-cross/arm-linux-gnueabihf/5/collect2 -plugin /usr/lib/gcc-cross/arm-linux-gnueabihf/5/liblto_plugin.so -plugin-opt=/usr/lib/gcc-cross/arm-linux-gnueabihf/5/lto-wrapper -plugin-opt=-fresolution=/tmp/ccUbRWT4.res -plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lgcc -plugin-opt=-pass-through=-lc -plugin-opt=-pass-through=-lgcc_s -plugin-opt=-pass-through=-lgcc --sysroot=/ --build-id --eh-frame-hdr -dynamic-linker /lib/ld-linux-armhf.so.3 -X --hash-style=gnu --as-needed -m armelf_linux_eabi -z relro -o VNAR_1971_JULY /usr/lib/gcc-cross/arm-linux-gnueabihf/5/../../../../arm-linux-gnueabihf/lib/../lib/crt1.o /usr/lib/gcc-cross/arm-linux-gnueabihf/5/../../../../arm-linux-gnueabihf/lib/../lib/crti.o /usr/lib/gcc-cross/arm-linux-gnueabihf/5/crtbegin.o -L/media/z/KINGSTON/BULEZ_LIB_RPI -L/usr/arm-linux-gnueabihf/lib -L/media/z/DEV/BLUEZ/BLUEZ_LIB -L/usr/lib/gcc-cross/arm-linux-gnueabihf/5 -L/usr/lib/gcc-cross/arm-linux-gnueabihf/5/../../../../arm-linux-gnueabihf/lib/../lib -L/lib/../lib -L/usr/lib/../lib -L/usr/lib/gcc-cross/arm-linux-gnueabihf/5/../../../../arm-linux-gnueabihf/lib ./src/MODULES/SOURCE_CODE/src/ESA_BASE_BAD.o ./src/MODULES/M_WIRE/CLASSWIRE.o ./src/MODULES/M_VNAR/CAD8302Detector.o ./src/MODULES/M_VNAR/C_DirectionalCoupler.o ./src/MODULES/M_VNA/CVNA.o ./src/MODULES/M_UTILITY/CUtility.o ./src/MODULES/M_TFT/CTEMPLATECLASS.o ./src/MODULES/M_TEMPLATE/CParameter.o ./src/MODULES/M_TEMPLATE/CParameter_test.o ./src/MODULES/M_TCP_IP/CTCPIPSERVER.o ./src/MODULES/M_TCP_IP/CTCPITCLIENT.o ./src/MODULES/M_SPI_TEST/CLASSSPITEST.o ./src/MODULES/M_SPI_LCM1602/C_TEMP_SPI.o ./src/MODULES/M_SPI_LCM1602/SAMPLE_CODE.o ./src/MODULES/M_SPI/CLASSFBDRIVER.o ./src/MODULES/M_SPI/CLASS_SPI.o ./src/MODULES/M_SPI/CLASS_SPI_BAD.o ./src/MODULES/M_SPI/C_FB.o ./src/MODULES/M_SPI/C_SPI.o ./src/MODULES/M_SPI/C_TFT.o ./src/MODULES/M_SPI/_touch.o ./src/MODULES/M_PCF8574/CLASSPCF8574.o ./src/MODULES/M_LCM1602_I2C/CLASSLCM1602.o ./src/MODULES/M_IOCTL/CIOCTL.o ./src/MODULES/M_IOCTL/CIOCTLGPIO.o ./src/MODULES/M_IOCTL/CIOCTLSPI.o ./src/MODULES/M_IOCTL/CLASSI2C.o ./src/MODULES/M_ILI9340_SPI_TFT/ili9340spi_rpi-master/demo.o ./src/MODULES/M_ILI9340_SPI_TFT/ili9340spi_rpi-master/fontx.o ./src/MODULES/M_ILI9340_SPI_TFT/ili9340spi_rpi-master/ili9340.o ./src/MODULES/M_ILI9340_SPI_TFT/ili9340spi_rpi-master/touch.o ./src/MODULES/M_ILI9340_SPI_TFT/ili9340spi_rpi-master/xpt.o ./src/MODULES/M_ILI9340_SPI_TFT/ili9340spi_rpi-master/xpt2046.o ./src/MODULES/M_ILI9340_SPI_TFT/CILI9340SPITFT.o ./src/MODULES/M_I2CIO/CLASSI2CIO.o ./src/MODULES/M_DDS_60/CDDS60.o ./src/MODULES/M_BLUETOOTH/CBT.o ./src/MODULES/M_BLUETOOTH/CBTTOOLS.o ./src/MODULES/M_BLUETOOTH/CDBUS.o ./src/MODULES/M_BLUETOOTH/CHCI.o ./src/MODULES/M_BCM2835_SPI_TFT/CBCM2835SPITFT.o ./src/MODULES/M_BCM2835_SPI_TFT/CBCMGPIO.o ./src/MODULES/M_BCM/CBCM.o ./src/MODULES/M_BASE_TEST/CBASE.o ./src/MODULES/M_BASE_TEST/CDEVICE.o ./src/MODULES/M_BASE_TEST/CINHER.o ./src/MODULES/M_ADS1115/CADS1115.o ./src/MODULES/M_ADA_ILI9341/ADAPORTILI9341.o ./src/MODULES/M_ADA/CADAILI9341.o ./src/MODULES/M_1602_HPP/M_1602_HPP.o ./src/MODULES/MODULE_SPI_DRIVER/CSPIDRIVER.o ./src/MODULES/MODULE_SPI/CSPI.o ./src/MODULES/MODULE_MAP_GPIO/CMAPGPIO.o ./src/MODULES/MODULE_INHERITED_GPIO_MAP/INHERITANCEBASE.o ./src/MODULES/MODULE_INHERITED_GPIO_MAP/INHERITANCEDERIVED.o ./src/MODULES/MODULE_INHERITED_GPIO_MAP/MODULEINHERITEDGPIOMAP.o ./src/MODULES/MODULE_I2C/CI2C.o ./src/MODULES/MODULE_GPIO/CGPIO.o ./src/MODULES/MODULE_BASE_GPIO_MAP/MODULEBASEGPIOMAP.o ./src/MODULES/MODULE_1602/C_1602.o ./src/MODULES/MODULE_1602/C_LCD2_CPP.o ./src/MODULES/MODULE_1602/C_SPI.o ./src/MODULES/MODULE_1602/C_SPI_LCD.o ./src/MODULES/MODULE_1602/C_SSP.o ./src/MODULES/MODULE_1602/C_gpio.o ./src/VNA_1022_BASE.o -lbluetooth -lstdc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc /usr/lib/gcc-cross/arm-linux-gnueabihf/5/crtend.o /usr/lib/gcc-cross/arm-linux-gnueabihf/5/../../../../arm-linux-gnueabihf/lib/../lib/crtn.o
/usr/lib/gcc-cross/arm-linux-gnueabihf/5/../../../../arm-linux-gnueabihf/bin/ld: cannot find /lib/arm-linux-gnueabihf/libc.so.6
/usr/lib/gcc-cross/arm-linux-gnueabihf/5/../../../../arm-linux-gnueabihf/bin/ld: cannot find /usr/lib/arm-linux-gnueabihf/libc_nonshared.a
/usr/lib/gcc-cross/arm-linux-gnueabihf/5/../../../../arm-linux-gnueabihf/bin/ld: cannot find /lib/arm-linux-gnueabihf/ld-linux-armhf.so.3
collect2: error: ld returned 1 exit status

Ideally to be able to option crosscomplier to use "foreign" links.

Would something like adding another prefix to the "_L" option work ?

modified 5-Jul-19 12:37pm.

Re: "crosslinking " - different architecture libraries - is is possible?

Richard MacCutchan1-Jul-19 20:56

Richard MacCutchan

1-Jul-19 20:56

Look at the error messages; there appear to be some files missing from the default location. You need to find out where they are stored and add that path to the linker options.

Re: "crosslinking " - different architecture libraries - is is possible?

leon de boer2-Jul-19 5:03

leon de boer

2-Jul-19 5:03

Do your standard apt-get update and install on libc somethings missing.

In vino veritas

Created .Dll from and .ocx using C++/CLI but interop is not loading in C#

Member 143147591-Jul-19 3:16

Member 14314759

1-Jul-19 3:16

System.Windows.Markup.XamlParseException: ''The invocation of the constructor on type 'CommonXFS.Interface.Utility.MainWindow' that matches the specified binding constraints threw an exception.' Line number '5' and line position '9'.'

InnerException:

FileNotFoundException: Could not load file or assembly 'Interop.NXCameraXLib.1.0, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified.

-----------------------------------------------------------------------------------------------------

Note I have tried both (x86) and (x64)

My DLl is not able to load as "Interop.NXCameraXLib.1.0 "(file from OCX adeed as reference) is not loading properly.

My Query !: Do we have any way to create an managed code(C++/CLI dll which don't need any dependency from any 3rd party if yes please share an example.
2) is there any way to sesolve siscussed error.

Return From DoModal with RadioButton

ForNow30-Jun-19 4:50

ForNow

30-Jun-19 4:50

Hi
IS there a way to return from DoModal without having a PUSH BUTTON with the value of IDOK ,IDCACEL or IDABORT I would like to have 3 radio buttons specifying 3 choice and return the value of one of those to DoModal

thanks

Re: Return From DoModal with RadioButton

Victor Nijegorodov30-Jun-19 6:43

Victor Nijegorodov

30-Jun-19 6:43

ForNow wrote:
IS there a way to return from DoModal without having a PUSH BUTTON with the value of IDOK ,IDCACEL or IDABORT

Yes. Just press the Enter button.

Re: Return From DoModal with RadioButton

Randor 30-Jun-19 7:13

Randor

30-Jun-19 7:13

Hi,

ForNow wrote:
Hi

Is there a way to return from DoModal without having a PUSH BUTTON with the value of IDOK?

Yes.

You would need to call the EndDialog function with the second argument set to the ID of your radio button. If you are not using Windows API and are using MFC instead... you would call CDialog::EndDialog

Best Wishes,
-David Delaune

Re: Return From DoModal with RadioButton

ForNow30-Jun-19 7:53

ForNow

30-Jun-19 7:53

I thought enddialog takes the value returned from DoModal

How can I pass return value to DoModal without one the predefined ways/values Microsoft is forcing me

I for instance would like to return the ID of a radio button which tell me which one of the options the user selected

Re: Return From DoModal with RadioButton

Randor 30-Jun-19 8:08

Randor

30-Jun-19 8:08

ForNow wrote:
I thought enddialog takes the value returned from DoModal

You have that backwards... DoModal() receives the return value from EndDialog()

ForNow wrote:
How can I pass return value to DoModal without one the predefined ways/values Microsoft is forcing me

C++

EndDialog(YourWindowHandle,YOUR_RADIO_ID); //If you're using Windows API
EndDialog(YOUR_RADIO_ID); //If you're using MFC Wrapper

Best Wishes,
-David Delaune

Re: Return From DoModal with RadioButton

ForNow30-Jun-19 9:43

ForNow

30-Jun-19 9:43

Thanks

My DoModal is being called from
My CMainFrame once returning to DoModal via EndDialog the Dialog box is destroyed but the class/object is still around ( I created the modal Dialog on the stack ) so the data in the class is still available until I exit the CMainFrame Routine

Also the only way to have a bad return code from UpdateData is to call pDx->fail which has the side effect of an exception which I would have to delete. if everything is okay I just call EnDialog notifying the CMainFrame which called DoModal of my selection
Thanks

Re: Return From DoModal with RadioButton

Randor 30-Jun-19 14:22

Randor

30-Jun-19 14:22

Hi,

I am happy to hear that you have it working. Smile | :)

ForNow wrote:
Also the only way to have a bad return code from UpdateData is to call pDx->fail which has the side effect of an exception which I would have to delete. if everything is okay I just call EndDialog notifying the CMainFrame which called DoModal of my selection

OK, let me know if you have any problems here. But from what you've described it sounds like the desired outcome.

Best Wishes,
-David Delaune

Re: Return From DoModal with RadioButton

ForNow30-Jun-19 16:24

ForNow

30-Jun-19 16:24

only one Issue UpdateData seems to always return TRUE even if I call pDX->fail

maybe I should set a global BOOL in my Modal Dialog Class and bypass checking return code from UpdateData

Thanks

Re: Return From DoModal with RadioButton

Randor 30-Jun-19 17:34

Randor

30-Jun-19 17:34

ForNow wrote:
only one Issue UpdateData seems to always return TRUE

That means UpdateData() succeeded. Can you explain to me why you need UpdateData to fail?

ForNow wrote:
even if I call pDX->fail

With my experience I am going to make a strong inference that your pDX variable is a pointer to a CDataExchange object. Can you explain to me why you need this to fail? If this fails a runtime error will be thrown... I can't even think of a valid reason you would want this.

The source for UpdateData() is inside wincore.cpp and you will find that the UpdateData() function constructs a new CDataExchange object and attaches it to your Cwnd object and performs DDX through there.

In other words... your line of code inside your class:

C++

pDX->Fail(); // This fails because it's a pointer to another CDataExchange object.

You should to open [Your Visual Studio Path]\VC\atlmfc\src\mfc\wincore.cpp and scroll down to the Updatedata() implementation where you will immediately understand why UpdateData() always returns TRUE; It creates a new CDataExchange object inside the function. You cannot force UpdateData() to fail by manipulating an external object.

Best Wishes,
-David Delaune

Re: Return From DoModal with RadioButton

Victor Nijegorodov30-Jun-19 21:37

Victor Nijegorodov

30-Jun-19 21:37

ForNow wrote:
only one Issue UpdateData seems to always return TRUE even if I call pDX->fail

maybe I should set a global BOOL in my Modal Dialog Class and bypass checking return code from UpdateData

Why do you need the "return code from UpdateData"?
Why do you need the UpdateData at all? There was a great essay about Avoid UpdateData of Joe Newcomer. I'd recommend you to check it out!

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