Sha256: 5889513de42d5a78f68b354e6b09c4f1d83f55dd579eddf0a71e558604e010f0
Contents?: true
Size: 518 Bytes
Versions: 10
Compression:
Stored size: 518 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
10 entries across 10 versions & 1 rubygems