title: read the data and skip parenthese with scanf
body: <p>I write a C program to pick the data from the the std input, which starts with a number  indicating the number of the data sets, then there are N pairs of data, in the form: (x y), so I write the code as below:</p>
  
  <pre><code>#include &lt;stdio.h&gt;
  
  int main()
  {
      int n_sets;
      scanf("%d", &amp;n_sets);
      int i;
      for(i = 0; i &lt; n_sets; ++i)
      {
          int m, n;
          scanf("(%d %d)", &amp;m, &amp;n);
          printf("%d\t%d\n", m, n);
      }
  
      return 0;
  }
  </code></pre>
  
  <p>but it doesn't work. After I input the number of the data set, the program print the uninitialized m&amp;n directly. But when I add a space before the <code>(%d %d)</code>, it works fine. Somebody can explain this?</p>