I have a simple problem.
#include <stdio.h>
#include <stdlib.h>
int main()
{
char c=getc(stdin);
if (c=='φ')
{
printf("in");
}
}
This piece of code does behave strangely.Try it yourself if you want to.If you input the Greek character φ in console,the if statement is false.If you change 'φ' to 'f' and repeat it works like a charm.Also been getting the warning multi-character character constant [-Wmultichar]|.Any advice?Thanks.
Very probably your terminal emulator is using UTF8 encoding. In that encoding φ (U+03C6 GREEK SMALL LETTER PHI) is two bytes : "\317\206" (octal string) or "\xCF\x86" (hex string)
You can find a lot of explanation about reading UTF8 in C e.g. this blog entry
Related
I have to save in a char[] the letter ñ and I'm not being able to do it. I tried doing this:
char example[1];
example[0] = 'ñ';
When compiling I get this:
$ gcc example.c
error: character too large for enclosing
character literal type
example[0] = 'ñ';
Does anyone know how to do this?
If you're using High Sierra, you are presumably using a Mac running macOS 10.13.3 (High Sierra), the same as me.
This comes down to code sets and locales — and can get tricky. Mac terminals use UTF-8 by default and ñ is Unicode character U+00F1, which requires two bytes, 0xC3 and 0xB1, to represent it in UTF-8. And the compiler is letting you know that one byte isn't big enough to hold two bytes of data. (In the single-byte code sets such as ISO 8859-1 or 8859-15, ñ has character code 0xF1 — 0xF1 and U+00F1 are similar, and this is not a coincidence; Unicode code points U+0000 to U+00FF are the same as in ISO 8859-1. ISO 8859-15 is a more modern variant of 8859-1, with the Euro symbol € and 7 other variations from 8859-1.)
Another option is to change the character set that your terminal works with; you need to adapt your code to suit the code set that the terminal uses.
You can work around this by using wchar_t:
#include <wchar.h>
void function(void);
void function(void)
{
wchar_t example[1];
example[0] = L'ñ';
putwchar(example[0]);
putwchar(L'\n');
}
#include <locale.h>
int main(void)
{
setlocale(LC_ALL, "");
function();
return 0;
}
This compiles; if you omit the call to setlocale(LC_ALL, "");, it doesn't work as I want (it generates just octal byte \361 (aka 0xF1) and a newline, which generates a ? on the terminal), whereas with setlocale(), it generates two bytes (\303\261 in octal, aka 0xC3 and 0xB1) and you see ñ on the console output.
You can use "extended ascii". This chart shows that 'ñ' can be represented in extended ascii as 164.
example[0] = (char)164;
You can print this character just like any other character
putchar(example[0]);
As noted in the comments above, this will depend on your environment. It might work on your machine but not another one.
The better answer is to use unicode, for example:
wchar_t example = '\u00F1';
This really depends on which character set / locale you will be using. If you want to hardcode this as a latin1 character, this example program does that:
#include <cstdio>
int main() {
char example[2] = {'\xF1'};
printf("%s", example);
return 0;
}
This, however, results in this output on my system that uses UTF-8:
$ ./a.out
�
So if you want to use non-ascii strings, I'd recommend not representing them as char arrays directly. If you really need to use char directly, the UTF-8 sequence for ñ is two chars wide, and can be written as such (again with a terminating '\0' for good measure):
char s[3] = {"\xC3\xB1"};
My main language is portuguese so we have some accented words (with á é í ó ú... etc characters) i'm trying to read and store those characters into a variable but it just doesn't work. If i just set it on the code it works, but if i ask the user for input it doesn't. Example code:
#include <stdio.h>
#include <stdlib.h>
#include <locale.h>
int main(int argc, char *argv[]) {
setlocale(LC_ALL, "Portuguese");
char test, test2; //The same still happens using unsigned char
test = 'í';
printf("Character: %c\n", test);
scanf(" %c", &test2); //The same still happens using fgets in case of a string
printf("Character: %c\n", test2);
system("pause");
return 0;
}
When compiled and executed the code shows:
Character: í
(wait for input, example:) í
character: ¡
if input is 'á' it prints ' '(space), 'é' prints ', ó prints '¢' and ú prints '£'.
I'm new into programming and stackoverflow, so sorry for any mistake i made, every help is appreciated, thank you.
oh, also I'm using Dev-c++ to compile if this make any difference.
You need to recognize that a char in C is a numeric type of size 1 byte. It actually is not exactly intended to keep the representation of a single language character item. (Sometimes called code point).
You do have two options to deal with this situation:
Use a character encoding that is single byte. (E.g. the proper
version of the iso-8859 family, iso-8859-1 in your case). This
will ensure that all characters will fit into a single byte.
deal with your input with proper mechanisms for multibyte
characters. You might look for char16_t or char32_t types and
maybe turn to using wchar_t and related library routines
I'm trying to save a character from the cyrillic alphabet in a char.
When I take a string from the console it saves it in the char array successfully but just initializing it doesn't seem to work. I get "programName.exe has stopped working" when trying to run it.
#include <stdio.h>
#include <conio.h>
#include <string.h>
#include <Windows.h>
#include <stdlib.h>
void test(){
char test = 'Я';
printf("%s",test);
}
void main(){
SetConsoleOutputCP(1251);
SetConsoleCP(1251);
test();
}
fgets ( books[booksCount].bookTitle, 80, stdin ); // this seems to be working ok with ascii.
I tried using wchar_t but I get the same results.
If you're using Russian Windows which uses Windows-1251 codepage by default, you can print the character encoded as a single byte using the old printf but you need to make sure that the source code uses the same cp1251 charset. Don't save as Unicode.
But the preferred way should be using wprintf with wide char string
void test() {
wchar_t test_char = L'Я';
wchar_t *test_string = L"АБВГ"; // or LPCWSTR test_string
wprintf(L"%c\n%s", test_char, test_string);
}
This time you need to save the file as Unicode (UTF-8 or UTF-16)
UTF-8 may be better, but it's trickier on Windows. Moreover if you use UTF-8 you cannot use a char to store Я because it needs more than 1 byte. You must use a char* instead
Note that main must return int, not void, and the above fgets must be called from inside some function
This could be solved, doing
void test()
{
char test = 'Я';
putchar(test);
}
But there is a catch: Since 'Я' is not an ASCII character, you might need to set appropriate locale before.
Moreover, only ASCII characters 32 - 126 are guaranteed to be printable, and the same symbol, on all systems.
I have an utf-8 character in chinese or arabic language. I need to get the value of that UTF-8 character, like getting a value of ASCII character. I need to implement it in "C". Can you please provide your suggestions?
For example:
char array[3] = "ab";
int v1,v2;
v1 = array[0];
v2 = array[1];
In the above code I will get corresponding ASCII values in v1 and v2. In the same way for UF8 string I need to get the value for each character in a string.
Only the C11 standard version of the C language offers UTF-8 support, so depending on what standard you are targeting, you can use the C11 features (<uchar.h>) or rely on a UTF library such as ICU.
There is no such thing as a UTF-8 character. There are Unicode characters and there are encodings for Unicode characters such as UTF-8.
What you probably want is to decode several bytes - encoded in UTF-8 and representing a single Unicode character - into the Unicode code point.
There's lot of C source code for this available in the net. Just google for UTF-8 decoding C.
Update:
What you're obviously looking for is a UTF-8 decoding for more than just one character, namely a function decoding an array of bytes (UTF-8 decoded text) into an array of ints (Unicode code points).
The answer remains the same: use Google. There's lot of C code for it out there.
C and C++ model is that the encoding is tied to the locale, so code using that model works for the encoding of the locale, whatever it is.
If you have a locale using UTF8 for the narrow encoding. See mbtowc(), mbrtowc(), mbstowcs and mbsrtocws(),they should be pretty straightforward to use.
With icu, you can skip through utf8 characters with U8_NEXT
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <unicode/utf.h>
#include <unicode/ustring.h>
int main(int argc, char **argv)
{
const char s[] = "日本語";
UChar32 c;
int32_t k;
int32_t len = strlen(s);
for (k = 0; k < len;) {
U8_NEXT(s, k, len, c);
printf("%d - %x\n", k, c);
}
return 0;
}
To compile with gcc utf.c -o utf $(icu-config --ldflags --ldflags-icuio)
The index k here indicates the starting offset of the encoding of your jth character. And c contains the unicode value (32 bits) of the character.
Edit:
I can only use stdio.h and stdlib.h
I would like to iterate through a char array filled with chars.
However chars like ä,ö take up twice the space and use two elements.
This is where my problem lies, I don't know how to access those special chars.
In my example the char "ä" would use hmm[0] and hmm[1].
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int main()
{
char* hmm = "äö";
printf("%c\n", hmm[0]); //i want to print "ä"
printf("%i\n", strlen(hmm));
return 0;
}
Thanks, i tried to run my attached code in Eclipse, there it works. I assume because it uses 64 bits and the "ä" has enough space to fit. strlen confirms that each "ä" is only counted as one element.
So i guess i could somehow tell it to allocate more space for each char (so "ä" can fit)?
#include <stdio.h>
#include <stdlib.h>
int main()
{
char* hmm = "äüö";
printf("%c\n", hmm[0]);
printf("%c\n", hmm[1]);
printf("%c\n", hmm[2]);
return 0;
}
A char always used one byte.
In your case you think that "ä" is one char: Wrong.
Open your .c source code with an hexadecimal viewer and you will see that ä is using 2 char because the file is encoded in UTF8
Now the question is do you want to use wide character ?
#include <stdio.h>
#include <stdlib.h>
#include <wchar.h>
#include <locale.h>
int main()
{
const wchar_t hmm[] = L"äö";
setlocale(LC_ALL, "");
wprintf(L"%ls\n", hmm);
wprintf(L"%lc\n", hmm[0]);
wprintf(L"%i\n", wcslen(hmm));
return 0;
}
Your data is in a multi-byte encoding. Therefore, you need to use multibyte character handling techniques to divvy up the string. For example:
#include <stdio.h>
#include <string.h>
#include <locale.h>
int main(void)
{
char* hmm = "äö";
int off = 0;
int len;
int max = strlen(hmm);
setlocale(LC_ALL, "");
printf("<<%s>>\n", hmm);
printf("%zi\n", strlen(hmm));
while (hmm[off] != '\0' && (len = mblen(&hmm[off], max - off)) > 0)
{
printf("<<%.*s>>\n", len, &hmm[off]);
off += len;
}
return 0;
}
On my Mac, it produced:
<<äö>>
4
<<ä>>
<<ö>>
The call to setlocale() was crucial; without that, the program runs in the "C" locale instead of my en_US.UTF-8 locale, and mblen() mishandled things:
<<äö>>
4
<<?>>
<<?>>
<<?>>
<<?>>
The questions marks appear because the bytes being printed are invalid single bytes as far as the UTF-8 terminal is concerned.
You can also use wide characters and wide-character printing, as shown in benjarobin's answer..
Sorry to drag this on. Though I think its important to highlight some issues. As I understand it OS-X has the ability to have the default OS code page to be UTF-8 so the answer is mostly in regards to Windows that under the hood uses UTF-16, and its default ACP code page is dependent on the specified OS region.
Firstly you can open Character Map, and find that
äö
Both reside in the code page 1252 (western), so this is not a MBCS issue. The only way it could be a MBCS issue is if you saved the file using MBCS (Shift-JIS,Big5,Korean,GBK) encoding.
The answer, of using
setlocale( LC_ALL, "" )
Does not give insight into the reason why, äö was rendered in the command prompt window incorrectly.
Command Prompt does use its own code pages, namely OEM code pages. Here is a reference to the following (OEM) code pages available with their character map's.
Going into command prompt and typing the following command (Chcp) Will reveal the current OEM code page that the command prompt is using.
Following Microsoft documentation by using setlocal(LC_ALL,"") it details the following behavior.
setlocale( LC_ALL, "" );
Sets the locale to the default, which is the user-default ANSI code page obtained from the operating system.
You can do this manually, by using chcp and passing your required code page, then run your application and it should output the text perfectly fine.
If it was a multie byte character set problem then there would be a whole list of other issues:
Under MBCS, characters are encoded in either one or two bytes. In two-byte characters, the first, or "lead-byte," signals that both it and the following byte are to be interpreted as one character. The first byte comes from a range of codes reserved for use as lead bytes. Which ranges of bytes can be lead bytes depends on the code page in use. For example, Japanese code page 932 uses the range 0x81 through 0x9F as lead bytes, but Korean code page 949 uses a different range.
Looking at the situation, and that the length was 4 instead of 2. I would say that the file format has been saved in UTF-8 (It could in fact been saved in UTF-16, though you would of run into problems sooner than later with the compiler). You're using characters that are not within the ASCII range of 0 to 127, UTF-8 is encoding the Unicode code point to two bytes. Your compiler is opening the file and assuming its your default OS code page or ANSI C. When parsing your string, it's interpreting the string as a ANSI C Strings 1 byte = 1 character.
To sove the issue, under windows convert the UTF-8 string to UTF-16 and print it with wprintf. Currently there is no native UTF-8 support for the Ascii/MBCS stdio functions.
For Mac OS-X, that has the default OS code page of UTF-8 then I would recommend following Jonathan Leffler solution to the problem because it is more elegant. Though if you port it to Windows later, you will find you will need to covert the string from UTF-8 to UTF-16 using the example bellow.
In either solution you will still need to change the command prompt code page to your operating system code page to print the characters above ASCII correctly.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <Windows.h>
#include <locale>
// File saved as UTF-8, with characters outside the ASCII range
int main()
{
// Set the OEM code page to be the default OS code page
setlocale(LC_ALL, "");
// äö reside outside of the ASCII range and in the Unicode code point Western Latin 1
// Thus, requires a lead byte per unicode code point when saving as UTF-8
char* hmm = "äö";
printf("UTF-8 file string using Windows 1252 code page read as:%s\n",hmm);
printf("Length:%d\n", strlen(hmm));
// Convert the UTF-8 String to a wide character
int nLen = MultiByteToWideChar(CP_UTF8, 0,hmm, -1, NULL, NULL);
LPWSTR lpszW = new WCHAR[nLen];
MultiByteToWideChar(CP_UTF8, 0, hmm, -1, lpszW, nLen);
// Print it
wprintf(L"wprintf wide character of UTF-8 string: %s\n", lpszW);
// Free the memory
delete[] lpszW;
int c = getchar();
return 0;
}
UTF-8 file string using Windows 1252 code page read as:äö
Length:4
wprintf wide character of UTF-8 string: äö
i would check your command prompt font/code page to make sure that it can display your os single byte encoding. note command prompt has its own code page that differs to your text editor.