block example in ruby

def total2(from, to, &block) 
  result = 0
  from.upto(to) do |num|
    if block 
      result += block.call(num)
    else 
      result += num
    end
  end
  return result
end

p total2(1, 10)
p total2(1, 10) {|num| num * 2}
p total2(1, 10) {|num| num ** 2}