I am rereading about structures and some of it just doesn't make sense right now.

What I need to do is have two structures :

The point structure stores the x and y coordinates of a point on a screen. // this makes sense of what I recall of graphing pointsCode:struct point { int x, y; }; struct rectangle ( struct point upper_left, lower_right; };

The rectangle structure stores the coordinates of the upper left and lower right corners of a rectangle // I have no idea what this means ; rectangles have 4 right angles thus 4 corners, why only coordinates of 2 corners ???

I need to write several functions using the above and with r being passed as an argument in rectangle structure // have no idea what this means in laymen's terms.

If I could get help with the first function I would appreciate it.

(1) compute the area of r.