Normal.c - normal distribution

normal.c

/*	normal.c		5-21-93
	Copyright (C)1993 Steven Whitney.
	Published under GNU GPL (General Public License) Version 2, with ABSOLUTELY NO WARRANTY.
	Initially published by http://25yearsofprogramming.com
	
	DeSmet C for the Heathkit H-100 computer. It uses some H-19 terminal escape codes.

	THIS BEGAN AS A C CONVERSION OF MY NORMAL.BAS PROGRAM, WHICH DROPS A PARTICLE 
	FROM THE TOP CENTER OF THE SCREEN, AND THEN MAKES RANDOM LEFT/RIGHT DECISIONS 
	ABOUT WHICH WAY TO GO ON THE WAY DOWN, AND AS A RESULT BUILDS A NORMAL DISTRIBUTION 
	AT THE BOTTOM OF THE SCREEN. HOWEVER, I THINK I ADDED THE "STICKY" ROUTINES FROM DLA.C, 
	SO IT MAKES STRANGE TREELIKE FORMATIONS AT THE SCREEN BOTTOM, INSTEAD.

*/
#include "stdio.h"

/* One version of DeSmet frand() had a bug. It sometimes returned a negative number. */
double posrnd()
{
	double r;
	do
	{
		r = frand();
	}
	while((r < 0.) || (r == 1.));
	return r;
}

main(argc,argv)
int argc;
char **argv;
{
char ch = '\0';			/* user input */
int i;					/* counter */
int x, y;				/* screen coordinates */
int xi, yi;				/* temp save of old coordinates */
int test;				/* cumulative test of surrounding points */
int seed, random;
int show = TRUE;		/* whether or not to show point's path */
int trail = FALSE;		/* erase current point before plotting next? */
int drawcirc = TRUE;	/* whether to start by drawing a circle */
FILE *infile;

cls();
puts("Usage:  NORMAL option option ...\n");
puts("\nOptions:\n");
puts("H         Display this help screen and exit\n");
puts("Lfname    Load file before starting\n");
puts("\n\nWhile program is running:\n");
puts("Q         Quit\n");	
puts("S         Toggle show-points flag\n");
puts("T         Toggle show point's entire path flag\n");
puts("\nEnter random number seed (-32768 to 32767): ");
scanf("%d",&seed);
srand(seed);

puts("\033x1\033E\033x5");	/* enable 25th line, cls, cursor off */

for(i = 1 ; i < argc ; i++)
{
	if(tolower(argv[i][0]) == 'h')
		exit(0);
	if(tolower(argv[i][0]) == 'l')
	{
		zedload(&(argv[i][1]));
		drawcirc = FALSE;
		break;
	}
}

if(drawcirc)
	line(0,224,639,224,1);

x = 320;
y = 1;
	
do
{
	if(ch == 't')
		trail = !trail;
	if(ch == 's')
		show = !show;				/* toggle */
	if(show)
		pset(x,y,2);

	test = 0;

	test |= point(x,y+1);
	test |= point(x-1,y);
	test |= point(x+1,y);

	/*
	test |= point(x+1,y+1);
	test |= point(x-1,y+1);
	*/
	
	
	if((test & ~2) != 0)		/* if it hits another point, */
	{							/* that is not red */
		pset(x,y,4);			/* it sticks to it */
		x = 320;				/* start again from center */
		y = 1;
	}
	else
	{
		xi = x; yi = y;
		y++;
		switch(random = (int)(posrnd() * 2))	
		{							
			case 0:  x += (int)(posrnd() * 2); break;	
			case 1:  x -= (int)(posrnd() * 2); break;
			default: 
				putchar(7);
				locate(24,1);
				printf("%d",random);
				break;	
		}
		if(show && !trail)  
			pset(xi,yi,0);				/* turn it off */
	}									/* before moving to next point */
}
while((ch = tolower(csts())) != 'q');
zedsave();
puts("\033z");							/* reset terminal */
exit(0);
}

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Copyright ©2008 Steven Whitney. Last modified 02/27/2008.