#!/bin/ch
#include <cgi.h>
#include <chplot.h>

int main() {
   double MinX, MaxX, Step, x, y;
   int pointsX, pointsY, i;
   chstrarray name, value;
   class CResponse Response;
   class CRequest Request;
   class CPlot plot;

   Request.getFormNameValue(name, value);
   MinX = atof(value[1]);
   MaxX = atof(value[2]);
   pointsX = atoi(value[3]);
   double x1[pointsX], y1[pointsX];

   Step = (MaxX - MinX)/(pointsX-1);
   for(i=0;i<pointsX;i++) {
     x = MinX + (i*Step);
     y = streval(value[0]);
     x1[i] = x;
     y1[i] = y;
   }

   Response.setContentType("image/png");
   Response.begin();
   plotxy(x1, y1, value[0], "X", "Y", &plot);
   /* output plot in color png file format */
   plot.outputType(PLOT_OUTPUTTYPE_STREAM, "png");         
   plot.plotting();
   Response.end();
}