In chapter 16, exercise 10b: The midpoint formula is required not the average length of the difference

[MKing8992]

Corrected the midpoint calculation in the function by using the proper midpoint formula: [(x_2 + x_1)/2, (y_2 + y_1)/2], rather than mistakenly calculating half the distance between points.

Prompt for chapter 16 exercise 10(b):

Given:

struct point {int x, y;);
struct rectangle { struct point upper_left, lower_right; };

(b) Compute the center of r, returning it as point value. If either the x or y coordinate of the center isn't an integer, store its truncated value in the point structure

The usage of [(x_2 - x_1)/2, (y_2 - y_1)/2] in the current solution below would not be the correct [x,y] coordinates

struct point rectangle_center(struct rectangle r) {
    return (struct point) {(r.lower_right.x - r.upper_left.x) / 2,
                           (r.lower_right.y - r.upper_left.y) / 2};
}