function int_add (x,y) dim res(1) as double res(0) = x(1,1)+y(1,1): res(1) = x(1,2)+y(1,2) int_add = res end function function int_subt (x,y) dim res(1) as double res(0) = x(1,1)-y(1,2): res(1) = x(1,2)-y(1,1) int_subt = res end function function int_mul (x,y) dim tmp(4) as double dim res(1) as double dim i as integer tmp(0) = x(1,1)*y(1,1): tmp(1) = x(1,1)*y(1,2) tmp(2) = x(1,2)*y(1,1): tmp(3) = x(1,2)*y(1,2) res(0) = tmp(0) res(1) = tmp(1) for i=1 to 3 if tmp(i) < res(0) then res(0) = tmp(i) if tmp(i) > res(1) then res(1) = tmp(i) next i int_mul = res end function function int_div (x,y) dim tmp(4) as double dim res(1) as double dim i as integer tmp(0) = x(1,1)/y(1,1): tmp(1) = x(1,1)/y(1,2) tmp(2) = x(1,2)/y(1,1): tmp(3) = x(1,2)/y(1,2) res(0) = tmp(0) res(1) = tmp(1) for i=1 to 3 if tmp(i) < res(0) then res(0) = tmp(i) if tmp(i) > res(1) then res(1) = tmp(i) next i int_div = res end function Function interval(x As Double) Dim res(2) As Double res(0) = x: res(1) = x interval = res End Function