/in/foo.cc: In function 'int main()':
/in/foo.cc:18:48: error: 'struct students' has no member named 'wy'; did you mean 'yy'?
    else if(a[j].zf=a[j+1].zf && a[j].yw<a[j+1].wy) swap(a[j],a[j+1]);
                                                ^~