how to calculate total number of days in a term excluding weekends

Declare 
 @counter int = 0,
 @strt date,
 @end date
Begin 
set @strt=(Select Distinct StartDate
		   From SchoolTerms
		   where EmisCode ='500226884' 
		   AND CurrentYear='2009'
		   AND Quater='Term1')
Set @end=(Select Distinct EndDate
		   From SchoolTerms
		   where EmisCode ='500226884' 
		   AND CurrentYear='2009'
		   AND Quater='Term1')
while (@strt<@end)
if DATEPART(weekday,@strt)<>7 or DATEPART(weekday,@strt)<> 1 
	set @counter+=1
	set @strt=@strt-1
print @strt
print @end
print @counter
End;

Msg 206, Level 16, State 2, Line 19
Operand type clash: date is incompatible with int