ruby_string

# new string
String a=String.new(str="hellssso");
print a+"\n";#hellossso 

#%用法
a % 123
print a+"\n"; #

# +用法
String opretor=String.new("hello");
print opretor+self.to_s+"\n"; #hello main self是main
 
# <<
str="hello";
str<<"world";
print str+"\n"; #helloWorld



str.concat(97);#追加一个字符
print str+"\n"; #hello worlda;

#字符串比较
print "abc" <=> "abcde"; #-1
print "abcde" <=> "abc";#1
print "abc"<=>"abc"+"\n";#0

#   "abcdef".casecmp("abcde")；同<==>一致

# str==obj;
String test=String.new("hello");
print "hello"==test; #true;
print test.to_s+"\n";#hello
print test.length;

#str=~obj;
test2="test";
print test2[0]+"test\n";
print test2.slice(0);
print test2;
if strs[0]==nil
    print "nil"
  end

#