Ruby没有将Fixnum隐式转换为String(TypeError)

Question

我试图回答Chris Pine的"学习编程"一书中的以下问题:

闰年.编写一个程序,要求开始年份和结束年份,然后将所有闰年放在它们之间(如果它们也是闰年,则包括它们).闰年是可被4整除的年份(如1984年和2004年).然而,被100整除的年份不是闰年(例如1800和1900),除非它们也可被400整除(例如1600和2000,实际上是闰年).真是一团糟!

运行代码时出现以下错误:

leap_year.rb:12:in +': no implicit conversion of Fixnum into String (TypeError) from leap_year.rb:12:in'

这是我的代码:

#leap years

puts 'What is the starting year?'
starting_year = gets.chomp
puts 'What is the ending year?'
ending_year = gets.chomp

while starting_year <= ending_year
  if starting_year%4 == 0 && (starting_year%100 != 0 && starting_year%400 == 0)
    puts starting_year 
  end 
  starting_year+=1
end

Answer 1

添加.to_i到您的gets.chomp通话中.你正试图对文本进行数学运算.当从控制台输入时,一切都以文本开头,即使它是数字外观文本.

Answer 2

这是因为输入来自gets.chompa String.你不能在a %上执行modulo()String.您需要先将其转换为整数.

试试这个...

puts 'What is the starting year?'
starting_year = gets.chomp.to_i
puts 'What is the ending year?'
ending_year = gets.chomp.to_i

while starting_year <= ending_year
  if starting_year%4 == 0 && (starting_year%100 != 0 && starting_year%400 == 0)
    puts starting_year 
  end 
  starting_year+=1
end

那现在有效吗？