#include <iostream>
#include <clocale>
#include <string>
int main() {
std::setlocale(LC_ALL, "en_US.utf8");
std::wstring str(L"Τὴ γλῶσσα μοῦ ἔδωσαν");
std::wcout << str << std::endl;
std::wcerr << str << std::endl;
}
This produces no output on the terminal.
How can I get it to produce UTF-8 output? I figure that ought to be something supported by C++.
I am aware of the utfcpp library, which I am using, but the question is specifically whether there is a stdlib way to print out UTF8.
I got it by following this.
std::setlocale(LC_ALL, ""); is the magic incantation.
This worked on my trivial test program. However my full program still completely fails at printing out wstrings.
That is fine (well, no, it is still somewhat alarming), I will avoid relying on stdlib, and do it myself with the help of utfcpp library, which is excellent. This way I can use cout and cerr for everything and all will be well.
Related
I'm trying to learn Unicode programming in Windows.
I have this simple program:
#include <iostream>
#include <string>
int main()
{
std::wstring greekWord = L"Ελληνικά";
std::wcout << greekWord << std::endl;
return 0;
}
However, it outputs nothing. Any ideas how to make it output Greek?
I tried adding non-Greek letters, and that didn't work quite right either.
The first thing to try is to make the program not dependent on the encoding of the source file. So use Unicode escapes not literal Unicode letters
std::wstring greekWord = L"\u0395\u03BB\u03BB\u03B7\u03BD\u03B9\u03BA\u03AC";
Having the incorrect encoding in the source file is only one thing of many things that could be preventing you from printing Greek. The other obvious issue is the ability of your terminal to print Greek letters. If it can't do that, or needs to be set up correctly so that it can then nothing you do in your program is going to work.
And probably you want to fix the source code encoding issue, so that you can use unescaped literals in your code. But that's dependent on the compiler/IDE you are using.
If you are outputting your cout to a normal console then the console doesn't usually support unicode text like greek, try setting it up for unicode text or find another way to output your data, like txt files or some gui,
There are two way to do this.
The old, non-standard Microsoft way is as follows:
#include <fcntl.h>
#include <io.h>
int main()
{
_setmode(_fileno(stdout), _O_U16TEXT);
_setmode(_fileno(stdin), _O_WTEXT);
// your code here
}
You will fild this everywhere, but this is not necessarily a good way to solve this problem.
The more standards-compliant way is as follows:
#include <locale>
int main()
{
std::locale l(""); // or std::locale l("en_US.utf-8");
std::locale::global(l); // or std::wcout.imbue(l); std::wcin.imbue(l);
// your code here
}
This should work with other modern compilers and operating systems too.
TRY this it works with me :
#include
#include <io.h>
#include <fcntl.h>
using namespace std;
int main() {
_setmode(_fileno(stdout),_O_U16TEXT);
wcout<<L"Ελληνικά";
setlocale(LC_ALL,"");
return 0;
}
I'm trying to get the C++ library to generate properly formatted USD output ($ sign, commas for every 1000s place etc).
I'm close, but I cannot get the right alignment to work:
#include <iostream>
#include <iomanip>
#include <locale>
using namespace std;
int main() {
double fiftyMil = 50000000.0; // 50 million bucks
locale myloc;
const money_put<char>& mpUS = use_facet<money_put<char> >(myloc);
cout.imbue(myloc);
cout << showbase << fixed;
cout << "A";
cout.width(30);
cout.setf(std::ios::right);
mpUS.put(cout, false, cout, ' ', fiftyMil * 100); // convert to cents
cout << "B" << endl;
return 0;
}
I'm getting:
A$50,000,000.00 B
I want to get:
A $50,000,000.00B
Any ideas why this isn't working?
I'm using the latest Solaris compiler (12.4)
Update:
It seems like the issue is with the C++ libraries included with the Solaris compiler. This is the workaround I used:
#include <iostream>
#include <iomanip>
#include <locale>
#include <sstream>
using namespace std;
string getFormattedCcy(double amt) {
ostringstream os;
static locale myloc;
static const money_put<char>& mpUS = use_facet<money_put<char> >(myloc);
os.imbue(myloc);
os << showbase << fixed;
mpUS.put(os, false, os, ' ', amt * 100);
return os.str();
}
int main() {
double fiftyMil = 50000000.0; // 50 million bucks
cout << "A";
cout.setf(std::ios::right);
cout.width(30);
cout << getFormattedCcy(fiftyMil);
cout << "B" << endl;
return 0;
}
You have a couple of problems--one with your code, another that looks like its in your implementation.
The problem in your code is pretty trivial. Since you're using a default-constructed locale, it should be using the "C" locale, which shouldn't write out the $ or thousands separators.
That part is easy to fix. Change: locale myloc; to: locale myloc(""); to get a localized locale (so to speak).
I doubt that'll fix the justification problem you're seeing though. That looks to me like it's a problem with the standard library you're using. When I run your code (with the correction above) I get what I'd expect:
A $50,000,000.00B
That's with Visual C++ though (and despite a compiler that conforms fairly poorly, its standard library is about as good as they come).
Also note that right justification is the default, so the line:
cout.setf(std::ios::right);
...should have no effect (but I suspect you knew that, and added it in the hope of getting it to work when it didn't otherwise).
As far as how to get things to work with the Sun Oracle compiler, the most obvious suggestion would probably be to switch standard libraries to one that works better. That leads to another question: whether to try to get a standard library to work with the compiler you're using, or switch to a different compiler such as CLang or gcc. From what I understand, 12.4 was a pretty serious improvement in terms of C++ conformance, but I don't think either the compiler or (apparently) the standard library is really competitive with gcc or Clang yet. OTOH, you may not have a choice, in which case essentially your only route is to build a different standard library with your existing compiler, and hope for the best. If you can't even do that...you could try setting the locale correctly, and just writing the number with std::cout << fiftyMil;, and hope it at least gives you commas as it should, then add the currency sign separately.
As an aside, if you do get an updated (C++11 or newer) library, you can use put_money to simplify the code quite a bit:
#include <iostream>
#include <iomanip>
#include <locale>
using namespace std;
int main() {
double fiftyMil = 50000000.0; // 50 million bucks
std::locale myloc("");
cout.imbue(myloc);
cout << "A" << showbase << setw(30) << put_money(fiftyMil * 100) << "B";
}
Picking up C++ and having a go at it on OS X 10.9 using XCode 5.0.2 and using Alex Allain as reference.
The following code compiles just fine and outputs correctly
#include <iostream>
#include <string>
using namespace std;
int main()
{
std::string user_first_name = "test";
std::cout << user_first_name << "\n";
return 0;
}
When I add a getline function, code appears to compile but with no output.
#include <iostream>
#include <string>
using namespace std;
int main()
{
std::string user_first_name = "test";
std::getline( std::cin, user_first_name, '\n' );
std::cout << user_first_name << "\n";
return 0;
}
In fact debug navigator has memory filling up with bars (although actual memory use is fixed at 276 KB). Why am I getting stumped on such a simple thing/concept?
I did a bit of digging around and its quite likely this is related to a text encoding issue. I'm using defaults which is Unicode (UTF-8). Encoding is not something I'm familiar with, never something I had to deal with when learning on Windows. How do I get past this?
I can't comment regarding the use of XCode or OS X, but it was my understanding that std::cin always gives you a narrow (single-byte) character stream. In Windows (at least with Visual Studio), I think it works whether you compile for UTF8 (single-byte for all ASCII characters) or UTF16 (2-bytes for all ASCII characters). The runtime library presumably does the conversion for you as necessary.
I'm not sure what "filling up with bars" means, but maybe it's just that you're looking at uninitialized memory. If you think that it is an encoding issue, perhaps try using wstring/wcin instead of string/cin and see if that helps.
I am sure this is a dumb question, but is there a straightforward way to print a Unicode character in C++ given its hex code? For instance: I know that the code for ❤ is 0x2764. Is there a way I can use its code to print it (either via printf or on a stream)?
For the record, I can print the character by writing:
cout << "\u2764" << endl;
but that requires knowing the value at compile time rather than using a variable.
Thanks
From a comment I see you're on OS X, which uses UTF-8 and has a sufficiently complete implementation of the C++11 library (libc++) for the following to work.
#include <codecvt> // wstring_convert, codecvt_utf8
#include <iostream> // cout
int main() {
std::wstring_convert<std::codecvt_utf8<char32_t>, char32_t> convert;
std::cout << convert.to_bytes(static_cast<char32_t>(0x2764)) << '\n';
}
This depends on the console working properly with UTF-8, which OS X's does.
Be sure to output wchar_t to the stream.
#include <iostream>
std::wcout << static_cast<wchar_t>(0x2764) << std::endl;
I know we can use
perror()
in C to print errors. I was just wondering if there is a C++ alternative to this, or whether I have to include this (and therefore stdio.h) in my program. I am trying to avoid as many C functions as possible.
You could do something like:
std::cerr << strerror(errno) << std::endl;
That still ends up calling strerror, so you're really just substituting one C function for another. OTOH, it does let you write via streams, instead of mixing C and C++ output, which is generally a good thing. At least AFAIK, C++ doesn't add anything to the library to act as a substitute for strerror (other than generating an std::string, I'm not sure what it would change from strerror anyway).
You could use the boost::system_error::error_code class.
#include <boost/system/system_error.hpp>
#include <cerrno>
#include <iostream>
void
PrintError(
const std::string& message,
int error
)
{
std::cerr << message << ": " <<
boost::system::error_code(
error,
boost::system::get_system_category()
).message()
<< std::endl;
}
int
main()
{
PrintError( "something went wrong!", EINVAL );
return 0;
}
it's a tad verbose, and somewhat overkill if you aren't already using the boost_system library.
With C++11, we have the <system_error> header, so you should be able to use:
std::error_code{errno, std::generic_category()}.message();
Example program:
#include <system_error>
#include <iostream>
int main() {
std::cout << std::error_code{errno, std::generic_category()}.message() << '\n';
}
This prints Success.
See also:
How to convert errno to exception using <system_error>
<system_error> categories and standard/system error codes (regarding whether to use generic_category or system_category)