Factorial up to 1000!

 We use biginteger, a type for real big numbers.

Font "Verdana"
form 80, 48
Cls , 0  ' 0 for non split display, eg 3 means we preserve the 3 top lines from scrolling/cla
Report {
	Factorial Task
	Definitions
               • The factorial of   0   (zero)   is defined as being   1   (unity).
               • The   Factorial Function   of a positive integer,   n,   is defined as the product of the sequence:
                                                                      n,   n-1,   n-2,   ...   1 
                                                                      
}
Cls, row  ' now we preserve some lines (as row number return here)
Module CheckIt {
	m=1u   ' 1u is biginteger
	k=width-tab  
	For i=1 to 1000 
		if pos>tab then print
		m*=i     
		Print @(0), format$("{0::-4} :", i);
		Report ltrim$(str$(m)), k
		' Report accumulate lines and stop at 3/4 of the screen (but not on printer)
		' so we can break this using this line: 
		while inkey$<>"": wait 1:end while: keyboard "         "			
	Next i
}
Checkit
while inkey$<>"": wait 1:end while			
push key$
drop