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typedef struct point { int x,y; } point;

typedef struct rect { point pt1, pt2; } rect;

point addpoint(point p1, point p2) {    /* add two points */

        p1.x += p2.x;

        p1.y += p2.y;

        return p1;

}

#define min(a, b) ((a) < (b) ? (a) : (b))

#define max(a, b) ((a) > (b) ? (a) : (b))

rect canonrect(rect r) {                /* canonicalize rectangle coordinates */

        rect temp;

        temp.pt1.x = min(r.pt1.x, r.pt2.x);

        temp.pt1.y = min(r.pt1.y, r.pt2.y);

        temp.pt2.x = max(r.pt1.x, r.pt2.x);

        temp.pt2.y = max(r.pt1.y, r.pt2.y);

        return temp;

}

point makepoint(int x, int y) {         /* make a point from x and y components */

        point p;

        p.x = x;

        p.y = y;

        return p;

}

rect makerect(point p1, point p2) {     /* make a rectangle from two points */

        rect r;

        r.pt1 = p1;

        r.pt2 = p2;

        return canonrect(r);

}

int ptinrect(point p, rect r) {         /* is p in r? */

        return p.x >= r.pt1.x && p.x < r.pt2.x

                && p.y >= r.pt1.y && p.y < r.pt2.y;

}

struct odd {char a[3]; } y = {'a', 'b', 0};

odd(struct odd y) {

        struct odd x = y;

        printf("%s\n", x.a);

}

main() {

        int i;

        point x, origin = { 0, 0 }, maxpt = { 320, 320 };

        point pts[] = { -1, -1, 1, 1, 20, 300, 500, 400 };

        rect screen = makerect(addpoint(maxpt, makepoint(-10, -10)),

                addpoint(origin, makepoint(10, 10)));

        for (i = 0; i < sizeof pts/sizeof pts[0]; i++) {

                printf("(%d,%d) is ", pts[i].x,

                        (x = makepoint(pts[i].x, pts[i].y)).y);

                if (ptinrect(x, screen) == 0)

                        printf("not ");

                printf("within [%d,%d; %d,%d]\n", screen.pt1.x, screen.pt1.y,

                        screen.pt2.x, screen.pt2.y);

        }

        odd(y);

        exit(0);

}