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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);
}
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