Data commit

Task/Penneys-game/UNIX-Shell/penneys-game.sh

@@ -0,0 +1,66 @@
+#!/bin/bash
+main() {
+  printf $'Penney\'s Game\n\n'
+  printf 'Flipping to see who goes first ... '
+
+  if [[ $(flip) == H ]]; then
+    printf 'I do.\n'
+    p2=$(choose_sequence)
+    printf 'I choose: %s\n' "$p2"
+  else
+    printf 'You do.\n'
+  fi
+
+  while true; do
+    read -p 'Enter your three-flip sequence: ' p1
+    p1=$(tr a-z A-Z <<<"$p1")
+    case "$p1" in
+     "$p2") printf 'Sequence must be different from mine\n';;
+     [HT][HT][HT]) break;;
+     *) printf $'Sequence must be three H\'s or T\'s\n';;
+    esac
+  done
+
+  if [ -z "$p2" ]; then
+    p2=$(choose_sequence "$p1")
+    printf 'I choose: %s\n' "$p2"
+  fi
+
+  printf '\nHere we go.  %s, you win; %s, I win.\n' "$p1" "$p2"
+  printf 'Flips:'
+
+  flips=
+  while true; do
+    flip=$(flip)
+    printf ' %s' "$flip"
+    flips+=$flip
+    case "$flips" in
+      *$p1) printf $'\nYou win!\n'; exit 0;;
+      *$p2) printf $'\nI win!\n'; exit 1;;
+    esac
+  done
+}
+
+choose_sequence() {
+  local result
+  if (( $# )); then
+    case "$1" in
+      ?[Hh]?) result=T;;
+      *) result=H;;
+    esac
+    result+="${1%?}"
+  else
+    result=$(flip)$(flip)$(flip)
+  fi
+  printf '%s\n' "$result"
+}
+
+flip() {
+  if (( RANDOM % 2 )); then
+    printf '%s\n' H
+  else
+    printf '%s\n' T
+  fi
+}
+
+main "$@"