C # for loop to enhance the efficiency of writing

// The following wording for much faster than the average for writing, tight, is probably the idea that one need only calculate the length 
. 1  int [] = {ARR . 1 , 2 , . 3 , . 4 , . 5 , . 6 };
 2  for ( int I = 0 , = iLen arr.length; I <iLen; I ++)    // must be displayed affirm not var 
. 3  {
 . 4  　　...........
 . 5 }