title: C printf difference between 0 flag & width attribute and precision flag
body: <p>I'm currently learning the <code>printf</code> function of libc and I don't understand, what is the difference between:</p>
  
  <pre><code>printf("Test : %010d", 10);
  </code></pre>
  
  <p>using the <code>0</code> flag and <code>10</code> as width specifier</p>
  
  <p>and</p>
  
  <pre><code>printf("Test : %.10d", 10);
  </code></pre>
  
  <p>using <code>10</code> as precision specifier</p>
  
  <p>That produce the same output: <code>Test : 0000000010</code></p>