Thread: Use a √ in a prog?

  1. #1
    Registered User Yamaten's Avatar
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    Use a √ in a prog?

    Hey guys, is it not possible to use the symbol √ in C? I've tried Alt + 251 and copy pasting it but it somehow turns into a letter v.That happens the moment I place it into the editor and not when I've run the program.

    Although this is purely for the aesthetic value of my program, I kinda find it irritating to use sqrt() in showing the solution to a formula.

    Using the alt numpad combo seems to result in a different symbol for each combo. I think i'm missing out on something here. Is the √ symbol really not available for output in C?

    I am using quincy btw. If this matters at all.

    P.S. I've just registered into this forum and haven't read the rules yet so please pardon if I've violated any of them. Thanks.

  2. #2
    misoturbutc Hodor's Avatar
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    No, it's not possible.

  3. #3
    Registered User Yamaten's Avatar
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    *sigh*

    Okay, thanks anyway.

  4. #4
    C++ Witch laserlight's Avatar
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    Nominal Animal covered something related to this recently: With C99, we are not bound to ASCII anymore! Let's support all character sets there are, okay? It's not difficult. In particular, a quick check shows that the character you have in mind should be L'\u221a'.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  5. #5
    misoturbutc Hodor's Avatar
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    Quote Originally Posted by laserlight View Post
    Nominal Animal covered something related to this recently: With C99, we are not bound to ASCII anymore! Let's support all character sets there are, okay? It's not difficult. In particular, a quick check shows that the character you have in mind should be L'\u221a'.
    That is not equivalent to calling sqrt() :/

    Edit: Oh. I misread the question. Sorry

  6. #6
    C++ Witch laserlight's Avatar
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    Quote Originally Posted by Hodor
    That is not equivalent to calling sqrt() :/
    Obviously, but equally obviously "use sqrt() in showing the solution to a formula" must refer to a string literal that involves the characters "sqrt" along with literal character parentheses, rather than to a call of sqrt from <math.h>, since "aesthetic value of my program" was stated. If instead the idea was to use some alternative to the sqrt function from <math.h>, then "no, it's not possible" must be a wrong answer since one can always implement an equivalent to that function.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  7. #7
    Registered User Yamaten's Avatar
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    Quote Originally Posted by laserlight View Post
    Nominal Animal covered something related to this recently: With C99, we are not bound to ASCII anymore! Let's support all character sets there are, okay? It's not difficult. In particular, a quick check shows that the character you have in mind should be L'\u221a'.
    Awesome. Thanks for the link.

  8. #8
    misoturbutc Hodor's Avatar
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    Quote Originally Posted by laserlight View Post
    [...] then "no, it's not possible" must be a wrong answer since one can always implement an equivalent to that function.
    Well I assume you saw my edit?

    Anyway, regarding the last part of your comment, since when can you have/name a function like double √(double); ?

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    Quote Originally Posted by Hodor View Post
    since when can you have/name a function like double √(double); ?
    That's not the question. The question is how to have that symbol displayed to the user.
    What can this strange device be?
    When I touch it, it gives forth a sound
    It's got wires that vibrate and give music
    What can this thing be that I found?

  10. #10
    misoturbutc Hodor's Avatar
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    Quote Originally Posted by Elkvis View Post
    That's not the question. The question is how to have that symbol displayed to the user.
    Yes, I realise that and acknowledged it in the edit to my post :/

    That's what "Edit: Oh. I misread the question. Sorry http://im.cprogramming.com/images/smilies/redface.png" means.

  11. #11
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    Quote Originally Posted by Hodor View Post
    since when can you have/name a function like double √(double); ?
    Since C99. Implementations can choose which extended characters they accept as identifiers. U+221A,, is not one that are required to be supported as an identifier, though.

    I tend to use GCC, and although -fextended-identifiers allows \uHHHH character constants in identifiers, it strictly restricts the identifiers to the minimum set the C99 standard specifies. There is an one line patch to allow non-ASCII characters "raw" in the identifiers. So, GCC does not allowin identifiers. It could (per C99 standard), but it chooses not to. Other compilers might.

    In general, using non-ASCII (rather, non-basic characters as the C standard defines it) characters in the source is a bit problematic, because unless you use UTF-8 everywhere, you have to worry about the source character set, especially when copying sources from one system to another. It's too much hassle for too little gain.



    As I explained in the post linked to above, using Unicode characters in strings and as character constants is no problem, however. We can even do it very portably, relying on C99 alone. Here's the on-topic example:
    Code:
    #include <stdlib.h>
    #include <string.h>
    #include <stdio.h>
    #include <locale.h>
    #include <wchar.h>
    #include <math.h>
    
    int main(int argc, char *argv[])
    {
        double value;
        char dummy;
        int arg;
    
        setlocale(LC_ALL, "");
        fwide(stdout, 1);
    
        if (argc < 2 || !strcmp(argv[1], "-h") || !strcmp(argv[1], "--help")) {
            fprintf(stderr, "\n");
            fprintf(stderr, "Usage: %s [ -h | --help ]\n", argv[0]);
            fprintf(stderr, "       %s NUMBER [ NUMBER ... ]\n", argv[0]);
            fprintf(stderr, "\n");
            fprintf(stderr, "This program calculates the square root of each NUMBER.\n");
            fprintf(stderr, "\n");
            return EXIT_FAILURE;
        }
    
        for (arg = 1; arg < argc; arg++)
            if (sscanf(argv[arg], " %lf %c", &value, &dummy) == 1) {
                fwprintf(stdout, L"\u221a(%s) = %f\n", argv[arg], sqrt(value));
                fflush(stdout);
            } else {
                fprintf(stderr, "%s: Not a number!\n", argv[arg]);
                return EXIT_FAILURE;
            }
    
        return EXIT_SUCCESS;
    }
    Note that only standard output is wide, here, unlike in my example in the other thread.

    The code is locale-aware. If you use a locale that uses different characters for numbers (digits), the code should Just Work.

    This code does not check the character sets used; it assumes it is some Unicode encoding. C99 did not standardize character set conversion utilities, but POSIX.1-2001 and POSIX.1-2008 did; the iconv() interface is very easy to use, and GNU libiconv (used in Linux) is available for non-POSIX systems too, including Windows.

    The code does not use a message cataloging library (like gettext) to provide the output in different languages. C99 does not standardize one, so I omitted it -- although GNU Gettext is ported to just about all OSes, and adding the support would have only added two or three lines to the code above.

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