Merge pull request #818 from aconconi/29-craps-lua

29_Craps Lua port

29_Craps/lua/README.md

@@ -1,3 +1,17 @@
 Original source downloaded [from Vintage Basic](http://www.vintage-basic.net/games.html)
 
-Conversion to [Lua](https://www.lua.org/)
+Conversion to [Lua](https://www.lua.org/) by Alex Conconi
+
+---
+
+### Lua porting notes
+
+-  The `craps_main` function contains the main game loop, which iteratively
+plays craps rounds by calling `play_round` and tracks winnings and losings.
+- Replaced the original routine that tries to scramble the random number
+generator with a proper seed initializer in Lua: `math.randomseed(os.time())`
+(as advised in the general porting notes). 
+- Added basic input validation to accept only positive integers for the
+wager and the answer to the "If you want to play again print 5" question.
+- "If you want to play again print 5 if not print 2" reads a bit odd but
+we decided to leave it as is and stay true to the BASIC original version.

29_Craps/lua/craps.lua

@@ -0,0 +1,149 @@
+--[[
+Craps
+
+From: BASIC Computer Games (1978)
+Edited by David H. Ahl
+
+    This game simulates the games of craps played according to standard
+    Nevada craps table rules. That is:
+    1. A 7 or 11 on the first roll wins
+    2. A 2, 3, or 12 on the first roll loses
+    3. Any other number rolled becomes your "point." You continue to roll;
+    if you get your point you win. If you roll a 7, you lose and the dice
+    change hands when this happens.
+
+    This version of craps was modified by Steve North of Creative Computing.
+    It is based on an original which appeared one day one a computer at DEC.
+
+
+Lua port by Alex Conconi, 2022
+--]]
+
+
+--- Throw two dice and return their sum.
+local function throw_dice()
+    return math.random(1, 6) + math.random(1, 6)
+end
+
+
+--- Print prompt and read a number > 0 from stdin.
+local function input_number(prompt)
+    while true do
+        io.write(prompt)
+        local number = tonumber(io.stdin:read("*l"))
+        if number and number > 0 then
+            return number
+        else
+            print("Please enter a number greater than zero.")
+        end
+    end
+end
+
+
+--- Print custom balance message depending on balance value
+local function print_balance(balance, under_msg, ahead_msg, even_msg)
+    if balance < 0 then
+        print(under_msg)
+    elseif balance > 0 then
+        print(ahead_msg)
+    else
+        print(even_msg)
+    end
+end
+
+
+--- Play a round and return winnings or losings.
+local function play_round()
+    -- Input the wager
+    local wager = input_number("Input the amount of your wager: ")
+
+    -- Roll the die for the first time.
+    print("I will now throw the dice")
+    local first_roll = throw_dice()
+
+    -- A 7 or 11 on the first roll wins.
+    if first_roll == 7 or first_roll == 11 then
+        print(string.format("%d - natural.... a winner!!!!", first_roll))
+        print(string.format("%d pays even money, you win %d dollars", first_roll, wager))
+        return wager
+    end
+
+    -- A 2, 3, or 12 on the first roll loses.
+    if first_roll == 2 or first_roll == 3 or first_roll == 12 then
+        if first_roll == 2 then
+            -- Special 'you lose' message for 'snake eyes'
+            print(string.format("%d - snake eyes.... you lose.", first_roll))
+        else
+            -- Default 'you lose' message
+            print(string.format("%d - craps.... you lose.", first_roll))
+        end
+        print(string.format("You lose %d dollars", wager))
+        return -wager
+    end
+
+    -- Any other number rolled becomes the "point".
+    -- Continue to roll until rolling a 7 or point.
+    print(string.format("%d is the point. I will roll again", first_roll))
+    while true do
+        local second_roll = throw_dice()
+        if second_roll == first_roll then
+            -- Player gets point and wins
+            print(string.format("%d - a winner.........congrats!!!!!!!!", first_roll))
+            print(string.format("%d at 2 to 1 odds pays you...let me see... %d dollars", first_roll, 2 * wager))
+            return 2 * wager
+        end
+        if second_roll == 7 then
+            -- Player rolls a 7 and loses
+            print(string.format("%d - craps. You lose.", second_roll))
+            print(string.format("You lose $ %d", wager))
+            return -wager
+        end
+        --  Continue to roll
+        print(string.format("%d  - no point. I will roll again", second_roll))
+    end
+end
+
+
+--- Main game function.
+local function craps_main()
+    -- Print the introduction to the game
+    print(string.rep(" ", 32) .. "Craps")
+    print(string.rep(" ", 14) .. "Creative Computing  Morristown, New Jersey\n\n")
+    print("2,3,12 are losers; 4,5,6,8,9,10 are points; 7,11 are natural winners.")
+
+    -- Initialize random number generator seed
+    math.randomseed(os.time())
+
+    -- Initialize balance to track winnings and losings
+    local balance = 0
+
+    -- Main game loop
+    local keep_playing = true
+    while keep_playing do
+        -- Play a round
+        balance = balance + play_round()
+
+        -- If player's answer is 5, then stop playing
+        keep_playing = (input_number("If you want to play again print 5 if not print 2: ") == 5)
+
+        -- Print an update on winnings or losings
+        print_balance(
+            balance,
+            string.format("You are now under $%d", -balance),
+            string.format("You are now ahead $%d", balance),
+            "You are now even at 0"
+        )
+    end
+
+    -- Game over, print the goodbye message
+    print_balance(
+        balance,
+        "Too bad, you are in the hole. Come again.",
+        "Congratulations---you came out a winner. Come again.",
+        "Congratulations---you came out even, not bad for an amateur"
+    )
+end
+
+
+--- Run the game.
+craps_main()