Orbit game in ruby

68_Orbit/ruby/orbit.rb

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+PAGE_WIDTH = 64
+
+def print_centered(msg)
+	spaces = " " * ((PAGE_WIDTH / msg.length).fdiv(2))
+	puts "#{spaces}#{msg}"
+end
+
+def print_instructions
+	puts "SOMEWHERE ABOVE YOUR PLANET IS A ROMULAN SHIP.
+THE SHIP IS IN A CONSTANT POLAR ORBIT.  ITS
+DISTANCE FROM THE CENTER OF YOUR PLANET IS FROM
+10,000 TO 30,000 MILES AND AT ITS PRESENT VELOCITY CAN
+CIRCLE YOUR PLANET ONCE EVERY 12 TO 36 HOURS.
+UNFORTUNATELY, THEY ARE USING A CLOAKING DEVICE SO
+YOU ARE UNABLE TO SEE THEM, BUT WITH A SPECIAL
+INSTRUMENT YOU CAN TELL HOW NEAR THEIR SHIP YOUR
+PHOTON BOMB EXPLODED.  YOU HAVE SEVEN HOURS UNTIL THEY
+HAVE BUILT UP SUFFICIENT POWER IN ORDER TO ESCAPE
+YOUR PLANET'S GRAVITY.
+YOUR PLANET HAS ENOUGH POWER TO FIRE ONE BOMB AN HOUR.
+AT THE BEGINNING OF EACH HOUR YOU WILL BE ASKED TO GIVE AN
+ANGLE (BETWEEN 0 AND 360) AND A DISTANCE IN UNITS OF
+100 MILES (BETWEEN 100 AND 300), AFTER WHICH YOUR BOMB'S
+DISTANCE FROM THE ENEMY SHIP WILL BE GIVEN.
+AN EXPLOSION WITHIN 5,000 MILES OF THE ROMULAN SHIP
+WILL DESTROY IT.
+BELOW IS A DIAGRAM TO HELP YOU VISUALIZE YOUR PLIGHT.
+                          90
+                    0000000000000
+                 0000000000000000000
+               000000           000000
+             00000                 00000
+            00000    XXXXXXXXXXX    00000
+           00000    XXXXXXXXXXXXX    00000
+          0000     XXXXXXXXXXXXXXX     0000
+         0000     XXXXXXXXXXXXXXXXX     0000
+        0000     XXXXXXXXXXXXXXXXXXX     0000
+180<== 00000     XXXXXXXXXXXXXXXXXXX     00000 ==>0
+        0000     XXXXXXXXXXXXXXXXXXX     0000
+         0000     XXXXXXXXXXXXXXXXX     0000
+          0000     XXXXXXXXXXXXXXX     0000
+           00000    XXXXXXXXXXXXX    00000
+            00000    XXXXXXXXXXX    00000
+             00000                 00000
+               000000           000000
+                 0000000000000000000
+                    0000000000000
+                         270
+X - YOUR PLANET
+O - THE ORBIT OF THE ROMULAN SHIP
+ON THE ABOVE DIAGRAM, THE ROMULAN SHIP IS CIRCLING
+COUNTERCLOCKWISE AROUND YOUR PLANET.  DON'T FORGET THAT
+WITHOUT SUFFICIENT POWER THE ROMULAN SHIP'S ALTITUDE
+AND ORBITAL RATE WILL REMAIN CONSTANT.
+GOOD LUCK.  THE FEDERATION IS COUNTING ON YOU.
+"
+end
+
+
+def get_yes_or_no()
+	while true
+		response = gets.chomp!.upcase
+		if response == "YES"
+			return true
+		elsif response == "NO"
+			return false
+		else
+			print("PLEASE TYPE 'YES' OR 'NO'")
+		end
+	end
+end
+
+def game_over(is_success)
+	if is_success
+		puts "YOU HAVE SUCCESSFULLY COMPLETED YOUR MISSION."
+	else
+		puts "YOU HAVE ALLOWED THE ROMULANS TO ESCAPE."
+		puts "ANOTHER ROMULAN SHIP HAS GONE INTO ORBIT."
+		puts "DO YOU WISH TO TRY TO DESTROY IT?"
+		return get_yes_or_no()
+	end
+end
+
+def play_game
+	rom_angle = rand(1...360)
+	rom_distance = rand(100...301)
+	rom_angular_velocity = rand(10...31)
+	hour = 0
+	while hour < 7
+		hour += 1
+		puts "\n\n"
+		puts "THIS IS HOUR #{hour}, AT WHAT ANGLE DO YOU WISH TO SEND"
+		puts "YOUR PHOTON BOMB?"
+
+		bomb_angle = gets.chomp!.to_f
+		puts "HOW FAR OUT DO YOU WISH TO DETONATE IT?"
+		bomb_distance = gets.chomp!.to_f
+		puts "\n\n"
+
+		rom_angle = (rom_angle + rom_angular_velocity) % 360
+		angular_difference = rom_angle - bomb_angle
+		c = Math.sqrt(rom_distance**2 + bomb_distance**2 - 2 * rom_distance * bomb_distance * Math.cos(angular_difference * Math::PI / 180))
+
+		puts "YOUR PHOTON BOMB EXPLODED #{sprintf('%.4f', 5)}*10^2 MILES FROM THE"
+		puts "ROMULAN SHIP."
+
+		if c <= 50
+			# Destroyed the Romulan
+			return true
+		end
+	end
+	return false
+end
+
+def main
+    print_centered "ORBIT"
+
+    print_instructions()
+
+    while true
+        success = play_game()
+        again = game_over(success)
+        if !again
+            return
+        end
+    end
+end
+
+if __FILE__ == $0
+  main
+end
+