RosettaCodeData/Task/Happy-numbers/Eiffel/happy-numbers.e
2015-02-20 00:35:01 -05:00

70 lines
1.1 KiB
Text

class
APPLICATION
create
make
feature {NONE} -- Initialization
make
-- Run application.
local
l_val: INTEGER
do
from
l_val := 1
until
l_val > 100
loop
if is_happy_number (l_val) then
print (l_val.out)
print ("%N")
end
l_val := l_val + 1
end
end
feature -- Happy number
is_happy_number (a_number: INTEGER): BOOLEAN
-- Is `a_number' a happy number?
require
positive_number: a_number > 0
local
l_number: INTEGER
l_set: ARRAYED_SET [INTEGER]
do
from
l_number := a_number
create l_set.make (10)
until
l_number = 1 or l_set.has (l_number)
loop
l_set.put (l_number)
l_number := square_sum_of_digits (l_number)
end
Result := (l_number = 1)
end
feature{NONE} -- Implementation
square_sum_of_digits (a_number: INTEGER): INTEGER
-- Sum of the sqares of digits of `a_number'.
require
positive_number: a_number > 0
local
l_number, l_digit: INTEGER
do
from
l_number := a_number
until
l_number = 0
loop
l_digit := l_number \\ 10
Result := Result + l_digit * l_digit
l_number := l_number // 10
end
end
end