116 lines
3.7 KiB
C
116 lines
3.7 KiB
C
/*
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Create a bar chart on the screen.
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The command line may contain the graphics mode. If no
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mode is specified, a default mode is used. EGA users
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may wish to try modes 14 or 16.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <conio.h>
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#include <string.h>
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#include <graphics.h>
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#include "screen.c" /* include function that sets screen mode */
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#define MODE CGA_320 /* default screen mode */
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#define CHARWIDTH 8
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#define CHARHEIGHT 8
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#define DATASIZE 15
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/*
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display a bar chart
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*/
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main(int argc, char *argv[]) {
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struct vconfig screen_data;
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int oldmode, mode;
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double data[DATASIZE] = {95.10, 96.11, 107.94, 135.76, 122.55,
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140.64, 164.93, 167.24, 211.28, 242.17,
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247.08, 277.72, 353.40, 330.22, 417.09};
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static char title[] = "S&P 500 Average (12/31)";
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static char pattern[] = {0, 0, 0, 0, 0, /* pattern for 0 color modes */
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0, 1, 1, 1, 0,
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0, 1, 0, 1, 0,
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0, 1, 1, 1, 0,
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0, 0, 0, 0, 0};
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double vinterval = 50.0; /* labeling interval for vertical axis */
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double maxval, value;
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double height, vscale;
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int width, base, i;
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int year;
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char color;
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char text[30];
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/* the screen mode may be specified on the command line */
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if (argc > 1) mode = atoi(argv[1]); else mode = MODE;
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oldmode = getvmode(); /* current screen mode */
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if ((mode = screen(oldmode,mode)) == -1) {
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puts("** Unable to set the screen to graphics mode **");
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setvmode(oldmode);
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return 1;
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}
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getvconfig(&screen_data); /* fetch the screen parameters */
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/* draw axes */
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pen_color(screen_data.colors-1);
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clrscrn2(0);
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base = screen_data.ypixels-CHARHEIGHT*2-4; /* allow space for title */
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move_to(CHARWIDTH*4,base+1);
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line_to(screen_data.xpixels-4,base+1); /* draw base line */
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move_to(CHARWIDTH*4,base+1);
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line_to(CHARWIDTH*4,4); /* draw vertical axis */
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/* calculate scale factors */
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maxval = data[0];
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for (i = 1; i < DATASIZE; ++i)
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if (maxval < data[i]) maxval = data[i];
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height = (double) (vinterval * (int) (maxval + vinterval)/vinterval );
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width = (screen_data.xpixels-CHARWIDTH*4-8)/DATASIZE;
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vscale = (base - 4) / height;
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/* label vertical axis */
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if (screen_data.colors > 2) pen_color(2);
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for (value = vinterval; value < height; value += vinterval) {
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move_to(CHARWIDTH*3+CHARWIDTH/2 ,base - (int)(value*vscale) );
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line_by(CHARWIDTH,0); /* axis marker */
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move_by(-CHARWIDTH*4-CHARWIDTH/2,-CHARHEIGHT/2);
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sprintf(text,"%3.0f",value);
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plots(text);
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}
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/* label horizontal axis */
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if ((CHARWIDTH*4+2) < width) {
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for (year = 1977; year <= 1991; year++) {
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move_to(CHARWIDTH*4+width*2/3+width*(year-1977)-CHARWIDTH*2,base+3);
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sprintf(text,"%4d",year);
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plots(text);
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}
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}
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else {
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for (year = 77; year <= 91; year++) {
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move_to(CHARWIDTH*4+width*2/3+width*(year-77)-CHARWIDTH,base+3);
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sprintf(text,"%2d",year);
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plots(text);
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}
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}
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/* label chart */
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move_to(screen_data.xpixels/2 - (CHARWIDTH*strlen(title))/2,
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base+CHARHEIGHT+3);
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plots(title);
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/* draw the bars */
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pen_color(1);
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color = 1;
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if (screen_data.colors == 2) fill_style(&pattern,5,5);
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else fill_style(&color,1,1);
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line_style(&color,1);
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for (i = 0; i < DATASIZE; ++i) {
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move_to(CHARWIDTH*4+width/3+width*i,base);
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box(width*2/3,(int)(-data[i]*vscale),1);
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}
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getch(); /* wait for a key */
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setvmode(oldmode);
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}
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