Count digits in an integer number

gistfile1.rb

# (1)
# Meh.
num = 6969
num.to_s.length #=> 4

# (2)
# Hm...
num = 6969
len = 0

begin
  len += 1
end while (num /= 10) > 0

p len #=> 4

# (3)
# Ah!..
num = 6969
Math.log10(num).floor.succ #=> 4

# But...
num = -6969
Math.log10(num).floor.succ #=> Math::DomainError: Numerical argument is out of domain - "log10"

# Well.
Math.log10(num.abs).floor.succ #=> 4

# Oh!
num = 0
Math.log10(num).floor.succ #=> FloatDomainError: -Infinity

# Mhm.
Math.log10(num.zero? && 1 || num).floor.succ #=> 1