title: Fork system call not exiting
body: <p>I've run the following code :</p>
  
  <pre><code>#include  &lt;stdio.h&gt;
  #include  &lt;sys/types.h&gt;
  int main()
  {
      fork();
      fork();
      fork();
      printf("hello\n");
      return 0;
  }
  </code></pre>
  
  <p>After printing the word "Hello" 8 times, the program is not exiting. What is the reason behind this?</p>