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  • Umesh

    plot

    I've not used graphics.h before. How can I plot a function say
    y=sin(x) ?

  • Walter Roberson

    #2
    Re: plot

    In article <1188332437.770 998.139350@x35g 2000prf.googleg roups.com>,
    Umesh <fraternitydisp osal@gmail.comw rote:
    >I've not used graphics.h before. How can I plot a function say
    >y=sin(x) ?
    Sorry, graphics.h is not part of the C programming language.

    There are a number of completely different graphics.h around.
    You need to consult a reference suitable for your implementation.


    Poking around a moment, I see an old example that might still
    be of value for you. Or maybe not, considering all the different
    graphics.h around.

    News: Latest Technology News - Stay updated with the latest tech news and find C and C++ programming resources on MYCPLUS.


    --
    Prototypes are supertypes of their clones. -- maplesoft

    Comment

    • Malcolm McLean

      #3
      Re: plot


      "Umesh" <fraternitydisp osal@gmail.comw rote in message
      news:1188332437 .770998.139350@ x35g2000prf.goo glegroups.com.. .
      I've not used graphics.h before. How can I plot a function say
      y=sin(x) ?
      >
      It's a platform-specific header.

      I've no idea how it works, but presumably you will need to intialise a
      graphics display. Then there will almost certainly be a function called
      something like plotxy(). It may take floats but will probably take integers.

      Your x axis will go from -PI to + PI, whilst your y axis will go from -1 to
      +1. However to really see the shape of the function, keep the scales the
      same, that's why we measure angles in radians.

      So all you need to do is maintain a double x, and take pixel steps from -PI
      to +PI. Call sin() to get y. Then convert from the mathematical coordinates
      to the pixel coordinates, making x = 0, y = 0 the centre pixel of the
      display, and call the plot function.


      --
      Free games and programming goodies.



      Comment

      • Joe Wright

        #4
        Re: plot

        Walter Roberson wrote:
        In article <1188332437.770 998.139350@x35g 2000prf.googleg roups.com>,
        Umesh <fraternitydisp osal@gmail.comw rote:
        >I've not used graphics.h before. How can I plot a function say
        >y=sin(x) ?
        >
        Sorry, graphics.h is not part of the C programming language.
        >
        There are a number of completely different graphics.h around.
        You need to consult a reference suitable for your implementation.
        >
        >
        Poking around a moment, I see an old example that might still
        be of value for you. Or maybe not, considering all the different
        graphics.h around.
        >
        News: Latest Technology News - Stay updated with the latest tech news and find C and C++ programming resources on MYCPLUS.

        >
        I'm sure you are trying to be helpful but any random graphics.h header
        is likely to be utterly useless. A given header might have a function
        prototype. The actual function must be in a library linked as we build
        the executable. The header and the library are married.

        If your implementation doesn't have a conio.h header for example,
        copying one from Borland or other system may not give you getch() or
        clrscr() or whatever. The functions are in the library, not the header.

        --
        Joe Wright
        "Everything should be made as simple as possible, but not simpler."
        --- Albert Einstein ---

        Comment

        • Walter Roberson

          #5
          Re: plot

          In article <ItGdnSCYG_UmB0 nbnZ2dnUVZ_vCkn Z2d@comcast.com >,
          Joe Wright <joewwright@com cast.netwrote:
          >Walter Roberson wrote:
          >In article <1188332437.770 998.139350@x35g 2000prf.googleg roups.com>,
          >Umesh <fraternitydisp osal@gmail.comw rote:
          >>I've not used graphics.h before. How can I plot a function say
          >>y=sin(x) ?
          >Poking around a moment, I see an old example that might still
          >be of value for you. Or maybe not, considering all the different
          >graphics.h around.
          >I'm sure you are trying to be helpful but any random graphics.h header
          >is likely to be utterly useless. A given header might have a function
          >prototype. The actual function must be in a library linked as we build
          >the executable. The header and the library are married.
          I did not suggest that Umesh copy a graphics.h file from somewhere.

          The article referenced shows an actual example of graphics
          functions in use in Windows, -likely- based upon the old Borland
          graphics library. The Borland graphics library is the one that
          came up most often for graphics.h and several more modern implementation
          libraries I found in my poking appear to deliberately retain
          compatability with the Borland facilities. And we've encountered
          Umesh often enough to know he is using Windows of some kind.

          Notice that my wording was that it was "an old example", rather
          than any kind of wording suggesting that I was pointing to a
          copy of graphics.h or pointing to an implementation library.
          "example" -- something to be examined and studied for learning
          purposes.
          --
          Programming is what happens while you're busy making other plans.

          Comment

          • user923005

            #6
            Re: plot

            On Aug 28, 1:20 pm, Umesh <fraternitydisp o...@gmail.comw rote:
            I've not used graphics.h before. How can I plot a function say
            y=sin(x) ?
            In the C language (all by itself) you can plot a character based
            graph.

            If you want to make pretty pictures, you will need to use a graphical
            extension to the language.

            PHIGS is one standards based extension.
            XWindows is another.
            GKS is another.
            CGM is another.

            Or you can use something like OpenGL or DirectX, which are proprietary
            but well accepted.

            Comment

            • user923005

              #7
              Re: plot

              On Aug 28, 1:20 pm, Umesh <fraternitydisp o...@gmail.comw rote:
              I've not used graphics.h before. How can I plot a function say
              y=sin(x) ?
              If you are interested in drawing pictures, you might try
              news:comp.graph ics.algorithms.
              Of course, you will read their FAQ before posting.

              Comment

              • Kenneth Brody

                #8
                Re: plot

                Malcolm McLean wrote:
                >
                "Umesh" <fraternitydisp osal@gmail.comw rote in message
                news:1188332437 .770998.139350@ x35g2000prf.goo glegroups.com.. .
                I've not used graphics.h before. How can I plot a function say
                y=sin(x) ?
                It's a platform-specific header.
                >
                I've no idea how it works, but presumably you will need to intialise a
                graphics display. Then there will almost certainly be a function called
                something like plotxy(). It may take floats but will probably take integers.
                [...]

                Not necessarily, although that's probably what the OP wants.

                Way (way, way!) back, I would plot things like that by placing
                the X axis down the page, and draw the X axis with "|" and place
                a "*" along the Y axis, using spaces to place the characters as
                needed.

                --------*--------
                | *
                | *
                | *
                | *
                | *
                | *
                *
                * |
                * |
                * |
                * |
                * |
                * |
                *

                Pure text, and easily done in pure ANSI C. (Although it does
                depend on a monospaced output device.)

                --
                +-------------------------+--------------------+-----------------------+
                | Kenneth J. Brody | www.hvcomputer.com | #include |
                | kenbrody/at\spamcop.net | www.fptech.com | <std_disclaimer .h|
                +-------------------------+--------------------+-----------------------+
                Don't e-mail me at: <mailto:ThisIsA SpamTrap@gmail. com>


                Comment

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