Custom ceiling

ceil_by_factor.rb

# Custom ceiling function
# Usage : If we want to ceil number by 50, it will ceil last two digit of the number into
# 0 -> 0
# (1..49) --> 50
# 50 --> 50
# (51..99) --> 100
# 123 --> 150
# Then use ceil_by_factor(number, 50)

# ceil_by_factor(123, 100) -> 200

def ceil_by_factor(num, fac)
  return num + (fac + (num / fac) * fac - (num % (fac + (num / fac) * fac))) % fac
end