title: #pragma omp parallel num_threads is not working
body: <pre><code>    #include&lt;omp.h&gt;
      #include&lt;stdio.h&gt;
      #include&lt;stdlib.h&gt;
  
      void main(int argc, int *argv[]){
  
  
     #pragma omp parallel num_threads(3)
     {
  
      int tid = omp_get_thread_num();
      printf("Hello world from thread = %d \n",tid);
      if(tid == 0){
          int nthreads = omp_get_num_threads();
          printf("Number of threads = %d\n",nthreads);
      }
     }
  
    }
  </code></pre>
  
  <p>I am learning OpenMP and I don't understand why it executes only one thread when I have specified the number of threads 3?
  The program ouptut:</p>
  
  <pre><code>   Hello world from thread = 0
     Number of threads = 1
  </code></pre>