title: 2d array filling
body: <p>I would like to fill 2d array, and this is what I do. However, it would give compile errors such as warning: value computed is not used and i dont understand why. I would appreciate if anyone could show me the problem and explain what could be done. thanks!</p>
  
  <pre><code>    #include &lt;stdio.h&gt;
      #include &lt;string.h&gt;
  
      int main()
      {
         int array1[4][4];
         int len = sizeof(array1) / sizeof(array1[0]);
         int wid = sizeof(array1[0]) / sizeof(array1[0][0]);
  
           int i, j , z = 0;
           //compile error
           for(i = 0, i &lt; len; i++)
           {
              for(j = 0, j &lt; wid; j++)
              {
                array1[i][j] = z;
              }
              z++;      
           }
  
           int a, b;
           for(a = 0, a &lt; len; a++)
           {
              for(b = 0, b &lt; wid; b++)
              {
                printf("%d", array1[a][b]);
               }
           }
             return 0;
           }
  </code></pre>