title: What does %s and %d mean in printf in the C language?
body: <p>I don't understand what the <code>%s</code> and <code>d%</code> do in this C code:</p>
  
  <pre><code>for (i=0;i&lt;sizeof(code)/sizeof(char*); i++) {
      printf("%s%d%s%d\n", "Length of String ", i, " is ", strlen(code[i]));
      str = code[i];
      printf("%s%d%s%c\n","The first character in string ", i, " is ", str[0]);
  }
  </code></pre>
  
  <p>I'm new to the C language and my background is in Java.</p>
  
  <ul>
  <li>What do the <code>%s%d%s%d</code> symbols denote?</li>
  <li>Why are there so many of them?</li>
  <li>Is the comma used here for concatenation instead of a <code>+</code>?</li>
  </ul>