I want to change text into float number for calculation in Qt
float test = ui.tableWidget->item(0, 1)->text().replace(",", ".", Qt::CaseSensitive).toFloat();
when I type 2.86, actually I see test = 2.85999990 in debug. How can I receive correctly what i typed ?
I can use this for showing
qDebug() << QString::number( test, 'f', 2 );
But I want a value for calculation, not for showing.
As #hauron already said this is format specific but normal behaviour. You might want to take a read on this.
Additionally you might also take a look at another answer here. Using some additional library may work for you, if applicable.
Related
I have a simple FMU file which contains a sine block that takes u as input and outputs y. In this case, u is set to equal to time. In my C++ code I have loaded the FMI library from FMILibrary and had done all the necessary steps up to a point where I want to give my input u a new value of pi(as 3.14). So I went:
fmistatus = fmi2_import_set_real(fmu, &uRef, 1, &pi);
while (timeCurrent < timeEnd){
fmistatus = fmi2_import_do_step(fmu, timeCurrent , stepSize, fmi2_true);
timeCurrent += stepSize;
}
u was still set to time even though I tried to give it a new value. Did I miss something?
PS. Is there anywhere I can find a more detailed description on the FMI library functions? Currently I can only find input output descriptions or did I miss something again.
UPDATE: After a few trials, I think this issue might be because I was trying to redefine my equation u = time. In other words when I change my u variable into RealInput block in openmodelica everything goes fine. So what if I really wants to redefine a certain equation? what do I have to do?
You shall not be able to set any variable in FMI - and especially not a variable with a binding equation - and I assume your Modelica model has "u=time;". Instead of having "u=time" you need to add a top-level input without any equation (so that the exported FMI has it as an input) - and then connect that to the sine-block.
Details:
For a co-simulation FMI the restriction on what you can set are in the state-diagram in section 4.2.4 of FMI2 specification.
Between fmi2DoStep you can only set Real variables that have causality="input" or causality="parameter" and variability="tunable" - and an input with an equation doesn't qualify.
Before starting the integration you could set it for other variables as well, but that is only guess-values for the initialization - and should not over-write the "u=time" equation.
I am developing a game using cocos2d-x and C++, and I need to load a bunch of YAML files for this application. I tried using the yaml-cpp library with quite good results.
The problem is that this library seems to be very unstable (at least under cocos2d-x on iOS), since almost 20% of the time it fails loading the same YAML file throwing "end of map not found", "invalid map element", or errors like these ones.
I followed the HowToParseADocument guide, so I think I got it correct. But, since it's not 100% reliable, I am looking for something more stable. Eg:
long size = 0;
unsigned char *yaml = FileUtils::getInstance()->getFileData("file.yml", "r", &size);
std::stringstream is;
is << yaml;
YAML::Parser parser(is);
YAML::Node doc;
while(parser.GetNextDocument(doc)) {
instance->settings = doc.Clone();
}
The parser usally breaks at the parser.GetNextDocument(doc) call. The document I am trying to read is plain YAML with key: value lists in this simple form:
# Comment
section1:
param1: value1
param2: value2
# Comment
section2:
param1: value1
param2: value2
Edit
I am not allowed to disclose the content of the original YAML file, but I can give you some information:
It only contains maps, and not arrays, aliases or other particular constructs
Those values are integers, float or strings
It has been linted with this free tool, with success.
The code I used to read it, posted up there, it's always in that form, and I do not modify it to make the app run correctly. It's just that the app starts and works or starts and does not work. Since I am changing nothing in the middle, I really do not understand what's happening.
It's a bit hard to guess at the solution because you won't provide an actual example, but:
Who owns the data at the unsigned char* returned by getFileData? If that function itself owns the data, then it is no longer valid after the function returns, and so all sorts of crazy stuff might happen.
To validate what's happening here (beyond looking at the implementation of getFileData), you could print out is.string() before calling YAML::Parser parser(is); and see if that prints the expected YAML.
When I was using up to qt4.8(qt quick 1.1) for gui then I am successfully able to print degree with \260 but when things got upgraded to qt5 and above then this stopped working. I searched on the net and found many relevant link such as (http://www.fileformat.info/info/unicode/char/00b0/index.htm) I tried but no help. Do I need to include some library for usinf UTF format or problem is sth else. Please some one help. What to do?
#Revised,
Here it is described what is being done.
First I am storing the printable statement in string text.
As in cpp function:-
sprintf(text, "%02d\260 %03d\260 ",latD, longD);
QString positionText(text.c_str());
return positionText;
And then using positionText in qml file to display on the window.
So, someone please answer what do I need to do to have degree in display?
Thanks.
Problem is simple you used \260 most probably inside Ansii C-string (const char []). In such cases Qt has use some codec to convert this to Unicode characters. For some reason when you change Qt version default codec was changed and this is why it stopped working.
Anyway your approach is wrong. You shouldn't use C-string which are codec depended (usually this leads to this kind of problems). You can define QChar const as QChar(0260) or best approach is to use tr and provide translation.
It would be best if you give representative example with string with degree character, then someone will provide you best solution.
Edit:
I would change your code like this:
const QChar degreeChar(0260); // octal value
return QString("%1%3 %2%3").arg(latD, 2, 10, '0').arg(longD, 3, 10, '0').arg(degreeChar);
or add translation which will handle this line:
return tr("%1degree %2degree").arg(latD, 2, 10, '0').arg(longD, 3, 10, '0');
Note that this translation for this line only have to be added always no mater what is current locale.
Try
return QString::fromLatin1(text);
or, if that doesn't work, another static QString::fromXXX method.
QT5 changed Qt's default codec from Latin-1 to UTF-8, as described here:
https://www.macieira.org/blog/2012/05/source-code-must-be-utf-8-and-qstring-wants-it/
Latin-1 and Unicode both use 176 (0xB0 or 0260) as the degree symbol, so your usage of it coincidentally worked, since it was interpreted as Latin-1 and converted to the same value in Unicode.
That first line could be changed to:
sprintf(text, "%02d\302\260 %03d\302\260 ",latD, longD);
As mentioned before, going directly to a QString is indeed better, but if you had to go through a std::string, you could simply substitute the UTF-8 encoding of Unicode 176, in which the lower 6 bits 110000 would have a 10 prepended, and the upper 2 bits 10, would have 110000 prepended in the first byte. This becomes: \302\260.
To easily print angles with degree symbols in console, try this:
#include <QDebug>
double v = 7.0589;
qDebug().noquote() << "value=" << v << QString(248);
Console output:
value= 7.0589 °
This works out-of-the-box under Windows.
I'd like to have my program output "cm2" (cm squared).
How do make a superscript 2?
As Zan said, it depends what character encoding your standard output supports. If it supports Unicode , you can use the encoding for ²(U+00B2). If it supports the same Unicode encoding for source files and standard output, you can just embed it in the file. For example, my GNU/Linux system uses UTF-8 for both, so this works fine:
#include <iostream>
int main()
{
std::cout << "cm²" << std::endl;
}
This is not something C++ can do on its own.
You would need to use a specific feature of your console system.
I am not aware of any consoles or terminals that implement super-script. I might be wrong though.
I was trying to accomplish this task for the purpose of making a quadratic equation solver. Writing ax² inside a cout << by holding ALT while typing 253 displayed properly in the source code only, BUT NOT in the console. When running the program, it appeared as a light colored rectangle instead of a superscript 2.
A simple solution to this seems to be casting the integer 253 as a char, like this... (char)253.
Because our professor discourages us from using 'magic numbers', I declared it as a constant variable... const int superScriptTwo = 253; //ascii value of super script two.
Then, where I wanted the superscript 2 to appear in the console, I cast my variable as a char like this...
cout << "f(x) = ax" << (char)superScriptTwo << " + bx + c"; and it displayed perfectly.
Perhaps it's even easier just to create it as a char to begin with, and not worry about casting it. This code will also print a super script 2 to the console when compiled and run in VS2013 on my Lenovo running Windows 7...
char ssTwo = 253;
cout << ssTwo << endl;
I hope someone will find this useful. This is my first post, ever, so I do apologize in advance if I accidentally violated any Stack Overflow protocols for answering a question posted 5+ years ago. Any such occurrence was not intentional.
Yes, I agree with Zan.
Basic C++ does not have any inbuilt functionality to print superscripts or subscripts. You need to use any additional UI library.
std::cout << cm\x00B2;
writes cm^2.
For super scripting or sub scripting you need to use ascii value of the letter or number.
Eg: Super scripting 2 for x² we need to get the ascii value of super script of 2 (search in google for that) ie - 253. For typing ascii character you have to do alt + 253 here, you can write a any number, but its 253 in this case.
Eg:-cout<<"x²";
So, now it should display x² on the black screen.
Why don't you try ASCII?
Declare a character and give it an ASCII value of 253 and then print the character.
So your code should go like this;
char ch = 253;
cout<<"cm"<<ch;
This will definitely print cm2.
I am using TWAIN in C++ and I am trying to set the DPI manually so that a user is not displayed with the scan dialog but instead the page just scans with set defaults and is stored for them. I need to set the DPI manually but I can not seem to get it to work. I have tried setting the capability using the ICAP_XRESOLUTION and the ICAP_YRESOLUTION. When I look at the image's info though it always shows the same resolution no matter what I set it to using the ICAPs. Is there another way to set the resolution of a scanned in image or is there just an additional step that needs to be done that I can not find in the documentation anywhere?
Thanks
I use ICAP_XRESOLUTION and the ICAP_YRESOLUTION to set the scan resolution for a scanner, and it works at least for a number of HP scanners.
Code snipset:
float x_res = 1200;
cap.Cap = ICAP_XRESOLUTION;
cap.ConType = TWON_ONEVALUE;
cap.hContainer = GlobalAlloc(GHND, sizeof(TW_ONEVALUE));
if(cap.hContainer)
{
val_p = (pTW_ONEVALUE)GlobalLock(cap.hContainer);
val_p->ItemType = TWTY_FIX32;
TW_FIX32 fix32_val = FloatToFIX32(x_res);
val_p->Item = *((pTW_INT32) &fix32_val);
GlobalUnlock(cap.hContainer);
ret_code = SetCapability(cap);
GlobalFree(cap.hContainer);
}
TW_FIX32 FloatToFIX32(float i_float)
{
TW_FIX32 Fix32_value;
TW_INT32 value = (TW_INT32) (i_float * 65536.0 + 0.5);
Fix32_value.Whole = LOWORD(value >> 16);
Fix32_value.Frac = LOWORD(value & 0x0000ffffL);
return Fix32_value;
}
The value should be of type TW_FIX32 which is a floating point format defined by twain (strange but true).
I hope it works for you!
It should work the way.
But unfortunately we're not living in a perfect world. TWAIN drivers are among the most buggy drivers out there. Controlling the scanning process with TWAIN has always been a big headache because most drivers have never been tested without the scan dialog.
As far as I know there is also no test-suite for twain-drivers, so each of them will behave slightly different.
I wrote an OCR application back in the 90th and had to deal with these issues as well. What I ended up was having a list of supported scanners and a scanner module with lots of hacks and work-arounds for each different driver.
Take the ICAP_XRESOLUTION for example: The TWAIN documentation sais you have to send the resolution as a 32 bit float. Have you tried to set it using an integer instead? Or send it as float but put the bit-representation of an integer into the float, or vice versa. All this could work for the driver you're working with. Or it could not work at all.
I doubt the situation has changed much since then. So good luck getting it working on at least half of the machines that are out there.