ruby 笔记之一

1.

#input a lot of di
puts 3/5

puts 5/3.1

=begin
#注释

nihao


=end

2.

puts 3/5;puts 3/5.0

puts "程序演示" /
"连接";

3.

#关键字，运算符,分隔符,组成了这门语言
print("===测试右边的值是否在左边的范围之内/n") ;
puts (0..9)===3.15 ;

a = 1 ; b = 1.0 ;
print("测试==比较的内容/n") ;
puts a == b ;

print("测试eql比较的类型和值/n") ;

puts a.eql?(b) ;

print("测试equal是比较地址/n") ;

puts a.equal?(b) ;
4.

# if then else end
a = 4 ; b = 4 ;
if a == b then
 
  print("相等/n") ;
else
  print("不相等") ;
end 

if a == 2 then
   print("a is value 2") ;
  
elsif a == 3 then
   print("a is value 3") ;
else
  print("a is value 4/n") ;

end

5.

#case when else end
a = 3 ;

case a
  when 1
       print("a is value 1/n") ;
      
  when 2
       print("a is value 2/n") ;
  else
       print("a is value 3") ;
end        

6.

# when end

a = 1 ;

while a<= 4
=begin
  is while in if print add ()
  is print warning:
  warning is don't put space before argument
  parenthese.
=end

  print "a=",a ;
  print "/n";
  a+=1 ;
 
end 

7.

# please calc 1..10 sum

a = 1 ;
sum = 0 ;
while a  <= 10
  sum += a ;
  a += 1 ;
end
print "1..10=",sum,"/n";

#把1..10之间的素质打印出来
print 5<3/2,"/n" ;
if  not 5<3/2 then
  print("nihao/n") ;
end
a = 2 ;
while a <= 100
   c = 1 ;   
   #只能被1和本身整除的数是素数
   b = 2 ;
   while b <= a/2
     if a%b == 0 then
       c = 2 ;
     end
     b += 1 ;
   end
  
   if c == 1 then
     print a," " ;
   end
   a += 1 ;
end