Sha256: 77a339e6a16368cbcebfa3afc5d40531b029eb99cc0ad4050b77db1cb603fc1c
Contents?: true
Size: 519 Bytes
Versions: 7
Compression:
Stored size: 519 Bytes
Contents
class Integer
# Calculate the factorial of an integer.
#
# 2.factorial #=> 2
# 3.factorial #=> 6
# 3.factorial #=> 24
#
# CREDIT: Malte Milatz
def factorial
return 1 if zero?
f = 1
2.upto(self) { |n| f *= n }
f
end
alias_method( :fac, :factorial )
#-- OLD CODE
#def factorial
# return 1 if self == 0
# #self == 0 ? 1 : ( self * (self-1).factorial )
# f = (1..self.abs).inject { |state, item| state * item }
# return self < 0 ? -f : f
#end
#++
end
Version data entries
7 entries across 7 versions & 2 rubygems