discrete and cominatorial math chapter 1_1

#/usr/bin/env julia


function trafficMethod( way::String, from::String = "Hsinchu", to::String = "Taipei" )::Function
	return 	function ()
				println("form $from to $to by $way")
			end
end

function count( a::Array, b::Array, ;rule = "product" )::Integer
	countA = length(a)
	countB = length(b)
	if countA <= 0 || countB <= 0
		error("illegal input")
	end
	if  rule == "sum"
		return countA + countB
	end
	if  rule == "product"
		return countA * countB
	end
	error("I don't know the option of $rule mean !\n")
end


println("""
Ex:
	Frank wants to go to Taipei.
	He can choose from bus services or train services to head from home to Hsinchu .
	From there, he can choose from 2 bus services or 3 train services to head to Taipei.
	{ bus: Kuo-Kuang Greyhound-Line , train: Amtrak Krtco Metro-Taipei }
	How many ways are there for Hsinchu to get to Taipei?
"""
)

byBus = [ trafficMethod("Kuo-Kuang") trafficMethod("Greyhound-Line") ]
byTrain = [ trafficMethod("Amtrak") trafficMethod("Krtco") trafficMethod("Metro-Taipei")  ]
println( "We have $(count( byBus, byTrain , rule = "sum" ) ) way to reach it\n" )

println("The rule of product");
player = [ "rock" "paper" "scissors" ]
println("Ex:\n	How many situation of \"rock paper scissors\" game for two player")
println("We have $( count( player, player ) ) situation")