title: For loop without any statement
body: <p>This program tells whether a given input is prime or not but I don't understand what exactly the for loop does here? It has no brackets and no statements in it.</p>
  
  <pre><code>int main(void)
  {
      int n;
  
      printf("Enter an integer number (&gt; 1): ");
      if (scanf("%d", &amp;n) != 1 || n &lt;= 1) {
          printf("Invalid input. Quit!\n");
          return -1;
      }
  
      int d;
      for (d = 2; n % d != 0; d++)
          ;
  
      if (d == n)
          printf("%d is prime\n", n);
      else
          printf("%d divides into %d\n", d, n);
  
      return 0;
  }
  </code></pre>