/* stick.tc - 3/27/9 - tct

dpf int n,d,p [
 /* display proper fraction n/d as decimal number
 /* with p digit precision 
 int w
 w=10*n/d
 if (p) [
  MC w,14
  dpf 10*n%d,d,p-1 /* recursive call
  ]
 ]

int last

rand [ /* returns random number in 1..2^31-1
 int m;m=2147483647
 int a;a=16807	
 last=last*a%m
 if (last<0) last=-last
 return last
 ]	

/* this was motivated by the "Sticky Probability Problem" in the Minitab manual on pg 51
/* two points along a straight stick are randomly selected. the stick is then broken at
/* these two points. find the probability that the three pieces can be arranged to form
/* a triangle. can be proved that p=.25

stick [
 pl "";ps "stick.tc - 3/27/9 - tct";pl "";pl ""
 ps "seed (e.g. 315) ";last=gn;if (last%2==0) ++last /* make odd
 pl "number of simulations (e.g. 1, 100, 200, 2000, 15000 etc.) "
 int ul;ul=gn
 int r1,r2,s,c,j,s1,s2,s3,k
 for (k=1;k<=10;++k) [
  c=0
  for (j=1;j<=ul;++j) [
   r1=(rand()+1)/2%1000000+1;r2=(rand()+1)/2%1000000+1
   /* r1 and r2 are in 1..1000000
   if (r1>r2) [s=r1;r1=r2;r2=s] /* r1<r2  
   s1=r1;s2=r2-r1;s3=1000000-r2+1
   if (s1>s2) [s=s1;s1=s2;s2=s]   
   if (s2>s3) [s=s2;s2=s3;s3=s]   
   if (s1>s2) [s=s1;s1=s2;s2=s] /* s1<=s2<=s3
   if ((s1+s2)>s3) ++c
   ]
  pl "probability of triangle =";pn c/ul;ps ".";dpf(c%ul,ul,4)
  ]
  pl ""
 ]