小编Ahm*_*ker的帖子

f.seek(0)这个脚本的目的是什么？rewind(current_file)如果文件已被程序打开,为什么我们需要？

input_file = ARGV[0]

def print_all(f)
    puts f.read()
end

def rewind(f)
    f.seek(0)
end

def print_a_line(line_count,f)
puts "#{line_count} #{f.readline()}"
end

current_file = File.open(input_file)

puts "First Let's print the whole file:"
puts # a blank line

print_all(current_file)

puts "Now Let's rewind, kind of like a tape"

rewind(current_file)

puts "Let's print the first line:"

current_line = 1
print_a_line(current_line, current_file)

是什么args意思，它之间有什么不同以及ARGV是否有区别？

 def puts_two(*args)
    arg1, arg2 = args
    puts "arg1: #{arg1}, arg2: #{arg2}"
    end

什么是is_a红宝石又是什么意思整数？

def prime(n)
  puts "That's not an integer." unless n.is_a? Integer
  is_prime = true
  for i in 2..n-1
    if n % i == 0
      is_prime = false
    end
  end
  if is_prime
    puts "#{n} is prime!"
  else
    puts "#{n} is not prime."
  end
end

prime(2)
prime(9)
prime(11)
prime(51)
prime(97)