Two Rectangles intersection

Question

I have two rectangles characterized by 4 values each :

Left position X, top position Y, width W and height H:

Answer 1

if (X1+W1<X2 or X2+W2<X1 or Y1+H1<Y2 or Y2+H2<Y1):
    Intersection = Empty
else:
    Intersection = Not Empty

If you have four coordinates – ((X,Y),(A,B)) and ((X1,Y1),(A1,B1)) – rather than two plus width and height, it would look like this:

if (A<X1 or A1<X or B<Y1 or B1<Y):
    Intersection = Empty
else:
    Intersection = Not Empty