/in/foo.cc: In function 'int main()':
/in/foo.cc:22:45: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
    if(a[j].zf=a[j+1].zf && a[j].yw<a[j+1].yw) swap(a[j],a[j+1]);
                                             ^