thread class doesn.t work properly

relates to threads and parallel programming

i saw a question on thread which was answered by someone .i tried the code answered by him and wrote it. i tried

   #include <iostream>
   #include <thread>
   using namespace std;
   void printx()
   {
    cout << "Hello world!!!!"<< endl;
    cout << "Hello world!!!!"<< endl; 
    cout << "Hello world!!!!"<< endl; 
    cout << "Hello world!!!!"<< endl;  
   }
   int main(){
    cout << "Hello world!!!!"<< endl; 
    thread t1(printx);
    //t1.join();
    t1.detach();
    cout << "Hello world!!!!"<< endl; 
   t1.join();
   return 0;
   }

and i received output as

Hello world!!!!

that was printed only once i don't understand shouldn't it be more number of times