how to code EA to do trailling only once a bar? pls help

 

i would like to do trailling stop only once a bar 

can anyone help pls? 

 
    
      static datetime bar_time=0;
      if(Time[0]!=bar_time)
        {
         bar_time=Time[0];
         //Trail stop code
        }
.
 
thank you
Reason: