/* bc.tc - tct - 1/14/16 */

int sd,ls

random int low,high [ /* returns a random integer between low and high */
 int range
 if (ls==0) ls=sd=99
 range=high-low+1
 ls=ls*sd
 if (ls<0) ls=-ls
 return low+(ls/8)%range
 ]

rev char s(0) [ /* reverse string s in place */
 int c,i,j
 s(strlen(s))='0'
 i=0;j=3
 while (i<j) [c=s(i);s(i)=s(j);s(j)=c;++i;--j]
 ]

itoa int n;char nst(0) [ /* convert integer n to string nst */
 int w
 w=0;nst(0)=n%10+'0';n=n/10
 while (n) [nst(++w)=n%10+'0';n=n/10]
 nst(++w)=0
 rev(nst)
 ]

nodup int x [
 char nst(4);int i,j
 itoa x,nst
 for (i=0;i<3;++i) [
  for (j=i+1;j<4;++j) [
   if ((nst(i)==nst(j))) return 0
  ]]
 return 1;
 ]

score int x,y [ /* count bulls and cows and return 10*b+c */
 char s1(5),s2(5);int i,j,b,c
 b=c=0
 itoa x,s1;itoa y,s2
 for (i=0;i<4;++i) [
  for (j=0;j<4;++j) [
   if (s1(i)==s2(j)) [
    if (i==j) ++b;else ++c
    break
  ]]]
 return 10*b+c
 ]

bullcow [

 pl "bc.tc - tct - 1/14/16"

 pl "";pl "Think of a 4-digit number. Use digits 0 thru 9. No repeating digits."
 pl "I'm gonna guess it."
 pl ""

 int ar(5039),scr,i,m,gs,tries,maxm,b,c
 
 m=-1
 for (i=0123;i<=9876;++i) if (nodup(i)) ar(++m)=i

 pl "Please enter a random number (should be odd) : "
 ls=sd=gn

 maxm=5039;tries=1
 gs=ar(random(0,maxm))
 pl "My guess : "
 if gs<1023 putchar '0'
 MC gs,14
 pl "Enter bulls (right digit, right place) : ";b=gn
 ps "Enter cows (right digit, wrong place) : ";c=gn
 scr=10*b+c

 while scr!=40 [ /* keep going till you have a perfect score */

  m=-1
  for (i=0;i<=maxm;++i) if (scr==score(gs,ar(i))) ar(++m)=ar(i)
  gs=ar(random(0,maxm=m))
  pl "My guess : "
  if gs<1023 putchar '0'
  MC gs,14
  pl "Enter bulls (right digit, right place) : ";b=gn
  ps "Enter cows (right digit, wrong place) : ";c=gn
  scr=10*b+c
  ++tries

  ]

 pl "It took me";pn tries
 if tries==1 ps " try!";else ps " tries!"
 pl "Beyond awesome.";pl ""

 ]