title: How to do += in TCL
body: <pre><code>set windowSize 0
  
  for {set i 0} {$i &lt; 14} {incr i} {
    set $windowSize [expr $windowSize + [$tcp($i) set cwnd_]]
  }
  puts "$windowSize"
  </code></pre>
  
  <p>This prints out zero, when the values being added are non zero. How to do this without a temp var? Holla if you love TCL. ...dead silence.</p>