const int pwm = 8 ;
int i ;
void setup() {
  // put your setup code here, to run once:
 pinMode(pwm,OUTPUT);
}

void loop() {
  // put your main code here, to run repeatedly:
// changing brightness using for loop

/*
FOR LOOP SYNTAX
for(initialization ; condition ; increment)
{
CODE
}    
*/

   for(i=0 ; i < 256 ; i++ )
   {
       analogWrite(pwm,i)  ; 		 // for loop from low to High
       delay(10);
   }

   for(i=255 ; i > 0 ; i-- )
   {
       analogWrite(pwm,i)  ;  		// for loop from high to low
       delay(10);
   }

}