initial commit

bash/darts/darts.sh

@@ -0,0 +1,82 @@
+#!/usr/bin/env bash
+#
+# external tools: none (only integer operations).
+#
+# V1   : Initial version.
+# V2   : Using reference instead of subshell, as of
+#         https://stackoverflow.com/questions/540298
+#        moved valid numbers in parseval function.
+# V3/4 : added some quotes following suggestions
+
+# set to mask to enable logs. 0: none, 255: all
+#((DEBUG=2#00001111))
+((DEBUG=2#00000000))
+
+# $1: log level (mask), then strings to display.
+debug () {
+    (( DEBUG & $1 )) && shift && echo "${@}" >&2
+}
+
+usage () {
+    echo "usage: darts x y" >&2
+    exit 1
+}
+
+shopt -s extglob
+
+# To be able to use bash only, all numbers will be miltiplied by 1,000.
+# Could be higher if we want more precision.
+#
+# So: 0.1 will be 100, 1 will be 1,000, 10 will br 10000, etc...
+
+# circles. as we will use Pythagoras' theorem, so square value calc here
+outer=$((  (10 * 1000 ) ** 2 ))
+middle=$(( ( 5 * 1000 ) ** 2 ))
+inner=$((  ( 1 * 1000 ) ** 2 ))
+
+debug 1 outer=$outer middle=$middle inner=$inner
+
+# basic args check: 2 args, and decimal numbers, which are:
+# optional +- sign, optional digits, optional . and optional digits
+(( ${#} != 2 )) && usage
+
+parseval() {
+    # integer and decimal parts, final value by ref
+    local int dec
+    local -n calc=$1
+
+    # check for valid decimal number
+    [[ ${2} != ?([-+])+([0-9])?(.*([0-9])) ]] && usage
+
+    IFS=. read int dec <<< "$2"
+    debug 2 ${int} ${dec}
+
+    # we accept up to 3 decimals: add 3 zeroes to dec, then keep 3 first digits
+    # So a decimal part of "1" will become 100, 01 will become 10, etc...
+    # we also take care of leadings 0 (octal notation), and remove leading "-".
+    dec="$dec"000
+    dec="10#"${dec:0:3}
+    int="10#"${int#-}
+
+    debug 2 mult ${int} ${dec}
+    calc=$(( (int*1000 + dec) ** 2 ))
+}
+
+parseval x "$1"
+parseval y "$2"
+total=$(( x+y ))
+debug 1 x=$x y=$y x+y=$total
+
+(( total <= inner  )) && echo 10 && exit 0
+(( total <= middle )) && echo 5 && exit 0
+(( total <= outer  )) && echo 1 && exit 0
+echo 0 && exit 0
+
+# emacs/vim settings.
+# Local Variables:
+# sh-basic-offset: 4
+# indent-tabs-mode: nil
+# comment-column: 60
+# fill-column: 80
+# End:
+# vim: set tabstop=4 expandtab: