do
return self.to_f.pow(e.to_f).to_i
end
+
+ # The factorial of `self` (aka `self!`)
+ #
+ # Returns `1 * 2 * 3 * ... * self-1 * self`
+ #
+ # assert 0.factorial == 1 # by convention for an empty product
+ # assert 1.factorial == 1
+ # assert 4.factorial == 24
+ # assert 9.factorial == 362880
+ fun factorial: Int
+ do
+ assert self >= 0
+ var res = 1
+ var n = self
+ while n > 0 do
+ res = res * n
+ n -= 1
+ end
+ return res
+ end
end
redef class Float
end
end
+redef class Sys
+ init
+ do
+ srand
+ end
+end
+
fun atan2(x: Float, y: Float): Float is extern "kernel_Any_Any_atan2_2"
fun pi: Float is extern "kernel_Any_Any_pi_0"
fun srand_from(x: Int) is extern "kernel_Any_Any_srand_from_1"