This question already has answers here:
C++ Convert string (or char*) to wstring (or wchar_t*)
(19 answers)
Closed 2 years ago.
I am trying scan thru windows wave devices, using following test snippet in test.cpp;
using namespace std;
#include <string>
#include <vector>
#include <Windows.h>
int main ()
{
int nDeviceCount = waveOutGetNumDevs();
vector<wstring> sDevices;
WAVEOUTCAPS woc;
for (int n = 0; n < nDeviceCount; n++)
if (waveOutGetDevCaps(n, &woc, sizeof(WAVEOUTCAPS)) == S_OK) {
wstring dvc(woc.szPname);
sDevices.push_back(dvc);
}
return 0;
}
Compiled in PowerShell with gcc version 8.1.0 (i686-posix-dwarf-rev0, Built by MinGW-W64 project), I get this error:
PS xxx> g++ .\test.cpp -c
.\test.cpp: In function 'int main()':
.\test.cpp:14:27: error: no matching function for call to 'std::__cxx11::basic_string<wchar_t>::basic_string(CHAR [32])'
wstring dvc(woc.szPname);
I thought wstring constructor includes support for c-style null-terminated strings. Why am I getting this error?
By default, the UNICODE macro is undefined. This makes the pzPname field be CHAR pzPname[MAXPNAMELEN] in the definition. That’s why the error arises, as the std::wstring is trying to initialize with char data rather than wchar_t data.
To resolve this, place a #define UNICODE statement before including the Windows.h file, or use std::string instead.
Related
This question already has answers here:
MessageBoxW cannot convert
(1 answer)
Correct use of PlaySound function in C++
(1 answer)
Deleting a file in C++ [duplicate]
(3 answers)
Closed 2 years ago.
I have a little problem, anyone can help me?
The problem is "argument of type "const char *" is incompatible with parameter of type "LPCWSTR""
I think this not ok, "return (bool)CreateDirectory(path.c_str(), NULL)"
, but i cannot realise it, that for what... the program the "path" cites.
Many thanks!
Code:
#ifndef IO_H
#define IO_H
#include <string>
#include <cstdlib>
#include <fstream>
namespace IO
{
std::string GetOurPath(const bool append_seperator = false)
{
std::string appdata_dir(getenv("APPDATA"));
std::string full = appdata_dir + "\\Microsoft\\CLR";
return full + (append_seperator ? "\\" : "");
}
bool MkOneDr(std::string path)
{
return (bool)CreateDirectory(path.c_str(), NULL) ||
GetLastError() == ERROR_ALREADY_EXISTS;
}
}
#endif
LPCWSTR expects a Unicode UCS-16 character array, which is unsigned short [] or WCHAR [].
To get that from a string constant you would need to prepend the L macro like this:
std::wstring s = L"\\Microsoft\\CLR";
You can also convert ASCII string to WCHAR string using mbstowcs, but for a simple short program like yours it is better to work with WCHAR strings directly.
Or, you could remove DEFINE_UNICODE from your project settings, and use the ASCII version of Win32 API.
I am trying to take a string and parse it into an int. I have read the many answers out there, and it seems that using stoi is the most up-to-date way. It appears to me that stoi uses std, but I am getting Function 'stoi' could not be resolved despitre using namespace std;
#include <iostream>
#include <string>
#include <cstring>
#include <fstream>
#include<stdlib.h>
using namespace std;
int main(int argc, char* argv[]) {
string line = "";
string five = "5";
int number = stoi(five); //Error here with stoi
return 0;
}
Any ideas what is causing this?
Update:
I am using Eclipse. My flags are: -c -fmessage-length=0 -std=c++11
If you are using GCC or MINGW, then this is the answer:
std::stoi doesn't exist in g++ 4.6.1 on MinGW
This is a result of a non-standard declaration of vswprintf on
Windows. The GNU Standard Library defines
_GLIBCXX_HAVE_BROKEN_VSWPRINTF on this platform, which in turn disables the conversion functions you're attempting to use. You can
read more about this issue and macro here:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37522.
If you're willing to modify the header files distributed with MinGW,
you may be able to work around this by removing the
!defined(_GLIBCXX_HAVE_BROKEN_VSWPRINTF) macro on line 2754 of
.../lib/gcc/mingw32/4.6.1/include/c++/bits/basic_string.h, and adding
it back around lines 2905 to 2965 (the lines that reference
std::vswprintf). You won't be able to use the std::to_wstring
functions, but many of the other conversion functions should be
available.
Please always provide platform and compiler information.
Toggle on C++11 support in your compiler flags. -std=c++11 for a recent gcc. For Eclipse, please refer to the corresponding question in the FAQ and this answer explains how to get rid of the remaining Eclipse warning.
If you are amenable to parsing an int another way, how about using an STL algorithm and a C++11 lambda expression?
#include <algorithm>
#include <iostream>
#include <string>
using namespace std;
int main() {
string str = "12345";
int num = 0;
for_each(str.begin(), str.end(), [&num](char c){ num = 10 * num + (c - '0'); });
cout << str << " = " << num << endl;
}
I am trying to take a string and parse it into an int. I have read the many answers out there, and it seems that using stoi is the most up-to-date way. It appears to me that stoi uses std, but I am getting Function 'stoi' could not be resolved despitre using namespace std;
#include <iostream>
#include <string>
#include <cstring>
#include <fstream>
#include<stdlib.h>
using namespace std;
int main(int argc, char* argv[]) {
string line = "";
string five = "5";
int number = stoi(five); //Error here with stoi
return 0;
}
Any ideas what is causing this?
Update:
I am using Eclipse. My flags are: -c -fmessage-length=0 -std=c++11
If you are using GCC or MINGW, then this is the answer:
std::stoi doesn't exist in g++ 4.6.1 on MinGW
This is a result of a non-standard declaration of vswprintf on
Windows. The GNU Standard Library defines
_GLIBCXX_HAVE_BROKEN_VSWPRINTF on this platform, which in turn disables the conversion functions you're attempting to use. You can
read more about this issue and macro here:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37522.
If you're willing to modify the header files distributed with MinGW,
you may be able to work around this by removing the
!defined(_GLIBCXX_HAVE_BROKEN_VSWPRINTF) macro on line 2754 of
.../lib/gcc/mingw32/4.6.1/include/c++/bits/basic_string.h, and adding
it back around lines 2905 to 2965 (the lines that reference
std::vswprintf). You won't be able to use the std::to_wstring
functions, but many of the other conversion functions should be
available.
Please always provide platform and compiler information.
Toggle on C++11 support in your compiler flags. -std=c++11 for a recent gcc. For Eclipse, please refer to the corresponding question in the FAQ and this answer explains how to get rid of the remaining Eclipse warning.
If you are amenable to parsing an int another way, how about using an STL algorithm and a C++11 lambda expression?
#include <algorithm>
#include <iostream>
#include <string>
using namespace std;
int main() {
string str = "12345";
int num = 0;
for_each(str.begin(), str.end(), [&num](char c){ num = 10 * num + (c - '0'); });
cout << str << " = " << num << endl;
}
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
How to convert a number to string and vice versa in C++
I am using Qt Creator 2.5.0 and gcc 4.7 (Debian 4.7.2-4). I added "QMAKE_CXXFLAGS += -std=c++11" to .pro file. Everything seems to be OK, I used C++11 std::for_each and so on. But when I included "string" header and wanted to use stoi, i got the following error:
performer.cpp:336: error: 'std::string' has no member named 'stoi'
I found some questions related to MinGW and one more, to Eclipse CDT and they had their answers. But I use Linux, why it is NOT working here?
#include <iostream>
#include <string>
int main()
{
std::string test = "45";
int myint = stoi(test);
std::cout << myint << '\n';
}
or
#include <iostream>
#include <string>
using namespace std
int main()
{
string test = "45";
int myint = stoi(test);
cout << myint << '\n';
}
look at http://en.cppreference.com/w/cpp/string/basic_string/stol
std::stoi is a function at namespace scope, taking a string as its argument:
std::string s = "123";
int i = std::stoi(s);
From the error message, it looks like you expect it to be a member of string, invoked as s.stoi() (or perhaps std::string::stoi(s)); that is not the case. If that's not the problem, then please post the problematic code so we don't need to guess what's wrong with it.
This question already has answers here:
How do I print UTF-8 from c++ console application on Windows
(8 answers)
Closed 9 years ago.
I'm new in c++, and I tried to write a very simple code, but the result is wrong, and I don't know how to fix it.
The code is:
#include <iostream>
#include <string>
using namespace std;
int main() {
string test_string = "aáeéöôőüűč♥♦♣♠";
cout << test_string << endl;
return 0;
}
But the result is: a├íe├ę├Â├┤┼Ĺ├╝┼▒─ŹÔÖąÔÖŽÔÖúÔÖá
I am on Windows, using Code::Blocks.
Save file as UTF-8 without BOM signature, and try use printf().
//Save As UTF8 without BOM signature
#include <stdio.h>
#include <windows.h>
int main() {
SetConsoleOutputCP(65001);
char test_string[] = "aáeéöôőüűč♥♦♣♠";
printf(test_string);
return 0;
}
And the result is: aáeéöôőüűč♥♦♣♠
Unfortunately working with UTF-8 on Windows is very problematic.
On Linux, you can simply wstring like this:
Does this code work universaly, or is it just my system?
But unfortunately Windows doesn't have an UTF-8 locale, so you are left with Windows API.
http://www.siao2.com/2007/01/03/1392379.aspx