title: operator && cannot be applied to boolean,char
body: <p>So I am working on a ModelViewController tic-tac-toe game homework and I am trying to check that if the board is empty at position xpos, ypos or not, but I got an error that says</p>
  
  <blockquote>
    <p>operator &amp;&amp; cannot be applied to boolean,char</p>
  </blockquote>
  
  <p>Why does this occur and how can I change it to make it work?</p>
  
  <pre><code>double xpos,ypos,xr,yr;
  char[][] position = {{' ',' ',' '},
               {' ',' ',' '},
               {' ',' ',' '}};
  
  public boolean isEmpty(int xpos, int ypos){
      int pos=xpos+3*ypos;
      boolean isPosWithinRange = pos&gt;=0 &amp;&amp; pos&lt;9 ;
      return isPosWithinRange &amp;&amp; position[xpos][ypos]=' ';
  }
  </code></pre>