/in/foo.cc: In function 'int main()':
/in/foo.cc:37:39: warning: 'y1' may be used uninitialized in this function [-Wmaybe-uninitialized]
             cout<<abs(x1)<<" "<<abs(y1)<<endl;
                                       ^
/in/foo.cc:37:28: warning: 'x1' may be used uninitialized in this function [-Wmaybe-uninitialized]
             cout<<abs(x1)<<" "<<abs(y1)<<endl;
                            ^~~