ceil(ndigits = 0) -> Integer | Float[permalink][rdoc]自身と等しいかより大きな整数のうち最小のものを返します。
例
1.2.ceil      # => 2
2.0.ceil      # => 2
(-1.2).ceil   # => -1
(-2.0).ceil   # => -2
1.234567.ceil(2)   # => 1.24
1.234567.ceil(3)   # => 1.235
1.234567.ceil(4)   # => 1.2346
1.234567.ceil(5)   # => 1.23457
34567.89.ceil(-5)  # => 100000
34567.89.ceil(-4)  # => 40000
34567.89.ceil(-3)  # => 35000
34567.89.ceil(-2)  # => 34600
34567.89.ceil(-1)  # => 34570
34567.89.ceil(0)   # => 34568
34567.89.ceil(1)   # => 34567.9
34567.89.ceil(2)   # => 34567.89
34567.89.ceil(3)   # => 34567.89
[SEE_ALSO] Float#floor, Float#round, Float#truncate