ruby入门示例1

#“从#开始到行尾是单行注释” puts 3/5 puts 3/5.0 =begin puts 6/5 puts 6/5.0 多行注释可以用=begin 和 =end 实际上，这是Ruby的内嵌文档Rdoc，类似javadoc ， 可以用命令 ri 从源文件生产文档。 =end #演示分行 puts 3/5 ; puts 3/5.0 puts "这里演示" / "连行" #循环 a=1 while a <10 print a," " a=a+1 end # E3.10-2.rb a=1 until a >=10 print a," " a=a+1 end# E3.10-3.rb for i in 1..9 print i," " end #演示break, next, redo, retry puts "演示break" c='a' for i in 1..4 if i == 2 and c =='a' c = 'b' print "/n" break end print i,c," " end puts "/n/n" puts "演示next" c='a' for i in 1..4 if i == 2 and c =='a' c = 'b' print "/n" next end print i,c," " end puts "/n/n" puts "演示redo" c='a' for i in 1..4 if i == 2 and c =='a' c = 'b' print "/n" redo end print i,c," " end puts "/n/n" puts "演示retry" c='a' for i in 1..4 if i == 2 and c =='a' c = 'b' print "/n" retry end print i,c," " end puts "/n/n" #求50以内的素数 for i in 2..50 #50以内 f=true for p in 2...i if i%p==0 f=!f break end end print i," " if f end #演示times, upto, downto, each, step 3.times { print "Hi!" } puts 1.upto(9) {|i| print i if i<7 } puts 9.downto(1){|i| print i if i<7 } puts (1..9).each {|i| print i if i<7} puts 0.step(11,3) {|i| print i } #求50以内的素数 $arr=[ ] #建立一个全局数组 $arr $arr[0]=2 def add_prime(n) #定义方法 将 n以内的奇素数加入$arr 3.step(n,2){|num|$arr < "acb" puts [5] <=> [4,9] puts (0..9)=== 3.14 puts ('a'..'f')=== 'c' # E3.9-1.rb x=3 case x when 1...2 print "x=",x,";在 1...2中" when 4..9,0 print "x=",x,";在 4..9,0中,或是0" else print "x=",x,";其它可能" end #类 class Person def initialize( name,age=18 ) @name = name @age = age @motherland = "China" end def talk puts "my name is "+@name+", age is "+@age.to_s if @motherland == "China" puts "I/'m Chinese." else puts "I/'m foreigner." end end attr_writer :motherland end p1=Person.new("kaichuan",20) p1.talk p2=Person.new("Ben") p2.motherland="ABC" p2.talk#E4.4-1.rb class Person def initialize( name,age=18 ) @name = name @age = age @motherland = "China" end def talk puts "my name is "+@name+", age is "+@age.to_s if @motherland == "China" puts "I am a Chinese." else puts "I am a foreigner." end end attr_writer :motherland end class Student < Person def talk puts "I am a student. my name is "+@name+", age is "+@age.to_s end end p3=Student.new("kaichuan",25);p3.talk p4=Student.new("Ben");p4.talk#E4.5-1.rb class Person def initialize( name,age=18 ) @name = name @age = age @motherland = "China" end def talk puts "my name is "+@name+", age is "+@age.to_s if @motherland == "China" puts "I am a Chinese." else puts "I am a foreigner." end end attr_writer :motherland end class Worker < Person def talk puts "I am a worker. my name is "+@name+", age is "+@age.to_s end end p5=Worker.new("kaichuan",30);p5.talk p6=Worker.new("Ben");p6.talk# E5.3-1.rb a=5 b="hh" puts "a = #{a}" puts "b = #{b}" # E5.3-2.rb a=5 print "a = ",a," ", a.class, "/n" a="hh" # a: 5 --> "hh" print "a = ",a," ", a.class, "/n" # E5.4-1.rb class Person def talk puts "Today is Saturday. " end end p1=Person.new p1.talk class Person def talk puts "Today is #@date. " end attr_accessor :date end p1.date="Sunday" p1.talk# E5.4-2.rb class Person def talk puts "Today is Saturday. " end end p1=Person.new p1.talk class Person undef :talk end #p1.talk