Good vs. Evil
- Thread starter Randomguy404
- Start date
-
The FTB Forum is now read-only, and is here as an archive. To participate in our community discussions, please join our Discord! https://ftb.team/discord
48 because
Code:
-- account.lua
-- from PiL 1, Chapter 16
Account = {balance = 0}
function Account:new (o, name)
o = o or {name=name}
setmetatable(o, self)
self.__index = self
return o
end
function Account:deposit (v)
self.balance = self.balance + v
end
function Account:withdraw (v)
if v > self.balance then error("insufficient funds on account "..self.name) end
self.balance = self.balance - v
end
function Account:show (title)
print(title or "", self.name, self.balance)
end
a = Account:new(nil,"demo")
a:show("after creation")
a:deposit(1000.00)
a:show("after deposit")
a:withdraw(100.00)
a:show("after withdraw")
-- this would raise an error
--[[
b = Account:new(nil,"DEMO")
b:withdraw(100.00)
--]]48 because
Code:
-- bisect.lua
-- bisection method for solving non-linear equations
delta=1e-6 -- tolerance
function bisect(f,a,b,fa,fb)
local c=(a+b)/2
io.write(n," c=",c," a=",a," b=",b,"\n")
if c==a or c==b or math.abs(a-b)<delta then return c,b-a end
n=n+1
local fc=f(c)
if fa*fc<0 then return bisect(f,a,c,fa,fc) else return bisect(f,c,b,fc,fb) end
end
-- find root of f in the inverval [a,b]. needs f(a)*f(b)<0
function solve(f,a,b)
n=0
local z,e=bisect(f,a,b,f(a),f(b))
io.write(string.format("after %d steps, root is %.17g with error %.1e, f=%.1e\n",n,z,e,f(z)))
end
-- our function
function f(x)
return x*x*x-x-1
end
-- find zero in [1,2]
solve(f,1,2)