struct.c

Go to the documentation of this file.

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);
}

---