Ruby中的逻辑运算以及符号作为方法名

#第十二课 逻辑运算
a,b = true, false
puts a && b #逻辑与运算
puts a || b #逻辑或运算
puts !a #取反
puts !b
puts c = (4 >3)
puts (4 > 3) && b

#三元运算
a, b = 4,5
puts c = (a > b) ? a : b

#范围运算
(2..5).each do |n|#从2到5闭区间
  print n
end

(2...5).each do |n|#从2到4左闭右开
  print n
end

#Ruby中符号也能够是方法名
class Student
  Version = 2#常量
  @@all_num = 2 #全局变量得要初始化否则要报错
  include Math #导入Mathm模块 Mix-in
  extend Math
  def initialize(name, num, sex)
    @name = name
    @num = num
    @sex = sex
  end

  class << self
    def class_fun
      puts "这是一个类方法"
    end

    def class_fun2
      puts "这也是一个类方法"
    end
  end

  def self.class_fun3
    puts "这是类方法的另一种写法"
  end
  #至关于Java中的get方法
  def get_name
    @name
    puts @@all_num += 1
  end

  def name
    @name
  end
  #至关于Java中的set方法
  def name=(value)
    @name = value
  end

  def set_name(name)
    @name = name
    puts @@all_num += 1
  end
end

class Student
  def expend
    puts "扩展类"
  end
end

class MiddleStudent < Student
  attr_reader :name
  attr_writer :name
  def initialize(name)
    @name = name
  end

  def sub_fun
    puts "这是子类的方法#{@name}"
  end
end

puts s = Student.new("young", 20, "男")
puts s.get_name
puts s.name
puts s.set_name("改了个名字")
puts s.name =("改了个好名字")
m = MiddleStudent.new("初中生")
puts m.name

class Vector
  attr_accessor :x, :y
  def initialize(x, y)
    @x = x
    @y = y
  end

  def +(value) #符号+作为方法名
    Vector.new(@x + value.x, @y + value.y)
  end

  def -(value)#符号-作为方法名
    Vector.new(@x - value.x, @y - value.y)
  end
end

p a = Vector.new(3, 5)
p b = Vector.new(6, 9)
 
p a + b
p a - b