title: Add operation on pointer
body: <pre><code>int a[3];
  int *j;
  a[0]=90;
  a[1]=91;
  a[2]=92;
  j=a;
  printf("%d",*j);
  printf("%d",&amp;a[0])
  printf("%d",&amp;a[1]);
  printf("%d",*(j+2));
  </code></pre>
  
  <p>here the pointer variable <code>j</code> is pointing to <code>a[0]</code>,which is 90;and address of <code>a[0]</code> is -20 is on my machine. So <code>j</code> is holding -20.
  And the address of <code>a[1]</code> is -18. So to get next variable I should use <code>*(j+2)</code>. because <code>j+2</code> will result in -18. but this is actually going on. To access <code>a[1]</code>. I have to use <code>*(j+1)</code>. but <code>j+1=-19</code>. Why is <code>j+1</code> resulting in -18 ?</p>