{ Calculation factorial values for numbers from 0 to 16 } 
 program facttest; 
 var 
 n: byte; 
 function factorial(n: byte): longint; 
 begin 
 if (n = 0) then 
 factorial := 1 
 else 
 factorial := n * factorial(n - 1); 
 end; 
 begin 
 for n := 0 to 16 do 
 begin 
 writeln(n, '! = ', factorial(n)); 
 end; 
 end.