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.
#! /usr/bin/tclsh
# HiLo.tcl - HaJo Gurt - 2005-06-20
# 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 input1 {prompt} {
#: Get input from user
puts -nonewline $prompt
set n [gets stdin] ;# implicit return
}
proc input {prompt} {
#: Get input from user, accept only numbers
set ok 0
while {$ok==0} {
puts -nonewline $prompt
set n [gets stdin]
set ok [string is integer -strict $n]
if {$ok==0} { puts "'$n' is invalid !\a" } ;# "\a": bell
}
return $n
}
proc inputA {prompt} {
#: Test: "Automatic" input, simulates user
puts -nonewline $prompt
incr ::x ;# Global variable x
}
proc random { {range 100} } {
#: Return a number in the range 0 .. $range-1
return [expr {int(rand()*$range)}]
}
#########.#########=#########^#########+#########*#########_#########$#####
proc HiLo { {Max 100} } {
#: Play the game
#set Secret 11 ;# Test
set Secret [expr {[random $Max] +1 }]
puts "Guess my number (1 .. $Max)"
set Try 0
while 1 {
incr Try
set Guess [ input "Your guess #$Try: " ] ;# Test: Replace "input" with "inputA"
if {$Guess < $Secret} { puts "$Guess is too low" }
if {$Guess > $Secret} { puts "$Guess is too high" }
if {$Guess == $Secret} { puts "$Guess is correct - You needed $Try guesses."; break }
if {$Try >= 12} { puts "You won't guess it..."; break } ;# Emergency-break
}
puts "Bye!"
}
#########.#########=#########^#########+#########*#########_#########$#####
set x 0 ;# Test: starting value for inputA
catch {console show} ;# when running in wish: open console-window
#HiLo 1024
HiLo ;# default: 100HJG 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 doesn't have useful information about this...
Is there a simpler way for "input" than gets workaround, e.g. without a gui ?
MG If you're using wish / Tk and have a GUI, you could have an entry widget where it can entered, and print the messages to a (deactivated, so it can't be altered) text widget. The entry widget would also allow for easy validation of the input - in the above, for instance, you could enter text or other non-numeric data, which would still work as being greater/less than the number in question.
HJG I'm not sure what you mean, concerning gets. In tclsh84 gets works fine, but in wish gets returns an empty string. So I would like this behavior of gets under wish fixed, preferably with something simpler than the gets workaround from RS, because GUI-elements in a text-environment look somewhat strange. - RS One should always use tclsh these days, and package require Tk where needed. This way, stdin should remain available...
HJG I tried that, but then scripts which use Tk keep their console window - that does not look good. I cannot get rid of it with "console hide", and "wm withdraw ." hides the Tk-window. On the page tclsh vs. wish I could not find advice about this, and it looks like most scripts here in the wiki use wish without "package require Tk".
LV If you are writing a graphical user interface, then don't use gets to get input from the user - use an entry widget or a text widget.
A version of HiLo with a full GUI is at HiLo2, and an international version at HiLo-international