[HJG] '''HiLo''' is a simple number-guessing game: for each guess, 
you get the answer "too high" or "too low", until you guess right.

With this game, you can explain how binary seaching works.

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 # HiLo.tcl - HaJo Gurt - 2005-06-19 
 # Simple Guess-the-number - game
 #
 # !! Run this in tclsh84 - wish has a bug with gets !!
 # See also: http://wiki.tcl.tk/10794 - [gets workaround]

  proc input {prompt} {
    puts -nonewline $prompt
    set n [gets stdin]
  }

 # "Automatic" input
  proc inputA {prompt} {
    puts -nonewline $prompt
    incr ::x
  }

 # Return a number in the range 0 .. $range-1
  proc random { {range 100} } {
    return [expr {int(rand()*$range)}]
  }

 #########.#########:#########^#########+#########-#########*#########$#####

  proc HiLo { {Max 100} } {
   #set Secret 11
    set Secret [expr {[random $Max] +1 }]

    puts "Guess my number (1 .. $Max)"
    set Try  0
    while 1 {
      incr Try
      set Num [ input "Your guess #$Try: " ]
      if {$Num <  $Secret} { puts "$Num is too low"  }
      if {$Num >  $Secret} { puts "$Num is too high" }
      if {$Num == $Secret} { puts "$Num is correct - You needed $Try guesses."; break }
      if {$Try >= 12}      { puts "You won't guess it..."; break }
    }
    puts "Bye!"
  }

 ###

  set x 0   ;# value for inputA
  catch {console show}

 #HiLo 1024
  HiLo       ;# default: 100
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It looks like the biggest problem with this program is the simple [gets] for reading from the user.
Even the FAQ at http://www.tcl.tk/man/tcl8.4/TclCmd/gets.htm and the tutorial at http://www.tcl.tk/man/tcl8.5/tutorial/tcltutorial.html don't have useful information about this...

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