/in/foo.cc: In function 'int main()':
/in/foo.cc:17:40: warning: unused variable 'ans' [-Wunused-variable]
  double d1,c,d2,p,you=0.0,fei=0.0,minn,ans=10000000.0;
                                        ^~~
/in/foo.cc:57:28: warning: 'hao' may be used uninitialized in this function [-Wmaybe-uninitialized]
    fei+=q[now].p*(((q[hao].d-q[now].d)/d2)-you); 
                     ~~~~~~~^