[amibroker] Trying to understand BarCount

[donpickdonpick]

Below is some code which finds buy and sell points based on ATR.  I am still 
learning afl code.

My question is regarding the construct:
for( i = 4; i < BarCount; i++ ) 

What is the value of BarCount?  Is this examining the 4 most recent barcounts?  

How many barcounts are being processed?  All of them available for a symbol? 

Thank you for your help.


for( i = 4; i < BarCount; i++ ) 
{ 
  if( L[ i ] >= L[ i-2 ] AND 
      L[ i-1 ] >= L[ i-2 ] AND 
      L[ i-3 ] >= L[ i-2 ] AND 
      L[ i-4 ] >= L[ i-2 ] ) 
  { 
    support[ i ] = L[ i - 2]; 
  } 
  else 
  if( L[ i ] > H[ i-1 ] * 1.0013 ) 
  { 
    support[ i ] = H[ i-1 ] * 0.9945; 
  } 
  else 
  if( L[ i ] > support[ i-1 ] * 1.1 ) 
  { 
     support[ i ] = support[ i-1 ] * 1.05; 
  } 
  else 
  { 
     support[ i ] = support[ i-1 ]; 
  } 

  if( H[ i ] > trends[ i-1 ] AND 
      H[ i-1 ] > trends[ i-1 ] ) 
  { 
      trends[ i ] = Max( trends[ i-1 ], support[ i ] ); 
  } 
  else 
  if( H[ i ] < trends[ i-1 ] AND 
      H[ i-1 ] < trends[ i-1 ] )   
  { 
      trends[ i ] = Min( trends[ i-1 ], resistance[ i ] ); 
  } 
  else 
  if( H[ i ] >= trends[ i-1 ] ) 
      trends[ i ] = support[ i ]; 
  else 
      trends[ i ] = resistance[ i ]; 
   
} 

Plot( trends, "Trends", colorRed ); 
Plot ( C, "Price", colorBlack, styleCandle );
//Plot( C, "Price", colorBlack, styleBar );  - Original
Buy = Cross( C, trends ); 
Sell = Cross( trends, H );