Coffeescript学习 万年历 以及 一元二次方程求解
#解一元二次方程
getDelta = (a,b,c) -> b * b - 4 * a * c;
getAnswer = (a,b,c) ->
delta = getDelta a,b,c
if delta < 0 then printAnswer null,null
else if delta > 0 then printAnswer (-b + Math.sqrt delta)/2*a, (-b - Math.sqrt delta)/2*a
else printAnswer -b/2*a
printAnswer = (a, b) ->
if not a? and not b? then "no answer"
else if a? and not b? then "answer is: #{a}"
else "answer is: #{a} and #{b}"
getAnswer2 = (a,b,c) ->
delta = getDelta a,b,c
switch
when delta < 0 then printAnswer null, null
when delta > 0 then printAnswer (-b + Math.sqrt delta)/2*a, (-b - Math.sqrt delta)/2*a
else printAnswer -b/2*a
alert getAnswer2 1,4,1
#斐波那契数列 fabonacci = (index) -> switch index when 0 then 1 when 1 then 1 else (fabonacci index-1) + (fabonacci index-2) print = (num)-> (fabonacci num for num in [1..num]) alert print 3 array = (fabonacci num for num in [0..32]) alert array alert print 5 ---------------------------------------------------- fabonacciMap = [] addMap = (index, value) -> fabonacciMap[index] = value value fabonacci = (index) -> if fabonacciMap[index]? then fabonacciMap[index] else switch index when 0 then addMap index,1 when 1 then addMap index,1 else a = fabonacci index-1 b = fabonacci index-2 addMap index, a+b array = (fabonacci num for num in [0..42]) alert array
addMap 是副作用函数，纯粹的函数式语言貌似不允许写这种函数
#=====================get random sort========================================= fun = (total) -> [1..total] rand = (total) -> Math.random() * total // 1 randArr = (total) -> (rand num for num in [1..total]) getRandSort = (num) -> ret=[] arr = fun num while arr.length > 0 randNum = rand arr.length value = arr.splice randNum,1 ret.push value ret #alert "value:"+value+" randNum:"+randNum+"\n arr:"+arr alert getRandSort 5
#万年历
trace = () ->
ret = ""
ret += "," + val for val in arguments
alert ret
anchor = {today: "2014-11-30", weekDay:7}
months = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]
getDateObj = (date) ->
[year, month, day] = date.split "-"
{year:parseInt year; month:parseInt month; day:parseInt day}
isLeapYear = (year) ->
if year%100 is 0 and year % 400 isnt 0 then false
else if year % 400 is 0 then true
else year % 4 is 0
getDays = (year) ->
if isLeapYear year then 366;
else 365
getDaysAmongYears = (smallYear, bigYear) ->
needReverse = bigYear < smallYear
if needReverse then [bigYear, smallYear] = [smallYear, bigYear]
if bigYear is smallYear then 0
else
ret = 0;
ret += getDays year for year in [smallYear..bigYear-1]
if needReverse then -ret else ret
#leap month is not considered in this method
getDaysAmongMonths = (smallMonth, bigMonth) ->
needReverse = bigMonth < smallMonth
if needReverse then [bigMonth, smallMonth] = [smallMonth, bigMonth]
if bigMonth is smallMonth or bigMonth is 1 then 0
else
ret = 0;
ret += months[month] for month in [smallMonth-1..bigMonth-2]
if needReverse then -ret else ret
floorDate2Year = (date) ->
obj = getDateObj date
offset = getDaysAmongMonths(1, obj.month) + obj.day
if isLeapYear(obj.year) and obj.month > 2 then offset += 1
{offset: offset, year: obj.year}
getDiffDays = (smallDate, bigDate) ->
big = floorDate2Year bigDate
small = floorDate2Year smallDate
yearDays = getDaysAmongYears small.year, big.year
offset = big.offset - small.offset
#trace big.offset, small.offset
yearDays + offset
getWeekDay = (date) ->
diffs = (getDiffDays anchor.today, date) % 7
diffs += 7 if diffs < 0
switch diffs
when 0 then "Sunday"
when 1 then "Monday"
when 2 then "Tuesday"
when 3 then "Wednesday"
when 4 then "Thursday"
when 5 then "Friday"
else "Saturday"
#alert getDiffDays "2012-3-28","2013-3-28"
alert getWeekDay "2012-2-29"
帮助： http://coffeescriptcookbook.com/chapters/arrays/creating-a-string-from-an-array