Question of regular expression

[stereoMatching]

Below is my code

string str2 = "1, 2, 3, 4, 5, 6, 7, 8";
string output;  
typedef std::tr1::sregex_token_iterator sti;  
const sti end;  
for(sti i(str2.begin(), str2.end(), regex(",\\s"), -1); i != end; ++i)  
{
  //output += "\"" + *i + "\", ";
  output += "\"";
  output += *i;
  output += "\", ";  
}      
cout<<output.substr(0, output.length() - 2)<<endl;

the result is

"1", "2, 3, 4, 5, 6, 7, 8"


But what I expected was

"1", "2", "3", "4", "5", "6", "7", "8"


How could I solve the problems?
Thanks a lot

ps:i am using the <regex> library of visual c++ 2008

[stereoMatching]

After a lot of struggles, I found out the problems
change

  
for(sti i(str2.begin(), str2.end(), regex(",\\s"), -1); i != end; ++i)

to

regex r(",\\s");
for(sti i(str2.begin(), str2.end(), r, -1); i != end; ++i)

never use temporary regex

[stereoMatching]

Now I have another question

  string s = "point(1,1,:)=[303 225 1];point(2,5,:)=[238,121,1];";
  regex pattern("((\\d+)\\s(\\d+)\\s(\\d+)|(\\d+),(\\d+),(\\d+))");
  const sregex_token_iterator end;
  std::vector<int> v;
  v.push_back(2);
  v.push_back(1);
      
  for(sregex_token_iterator i(s.begin(), s.end(), pattern, v); i != end; )
  {
    cout<<*i++;
    cout<<" "<<*i++<<endl;
  }    
  cout<<endl;

I hope the output could be

225 303
121 238

But the results are totally wrong

The wrong results are

303 303 225 1
238, 121,1


I have no idea what is happening
How could I solve the problems?
Thanks a lot

PS:

regex pattern("(\\d+),(\\d+),(\\d+)");

or

regex pattern("(\\d+)\\s(\\d+)\\s(\\d+)");

are fine, but they would only output "225 303" or "121 238"