/in/foo.cc: In function 'void work()':
/in/foo.cc:42:27: warning: 'qy' may be used uninitialized in this function [-Wmaybe-uninitialized]
     X4=2*midx-qx;Y4=2*midy-qy;
                     ~~~~~~^~~
/in/foo.cc:42:14: warning: 'qx' may be used uninitialized in this function [-Wmaybe-uninitialized]
     X4=2*midx-qx;Y4=2*midy-qy;
        ~~~~~~^~~
/in/foo.cc:41:35: warning: 'my' may be used uninitialized in this function [-Wmaybe-uninitialized]
     double midx=(nx+mx)/2,midy=(ny+my)/2;
                                ~~~^~~~
/in/foo.cc:41:20: warning: 'mx' may be used uninitialized in this function [-Wmaybe-uninitialized]
     double midx=(nx+mx)/2,midy=(ny+my)/2;
                 ~~~^~~~
/in/foo.cc:41:35: warning: 'ny' may be used uninitialized in this function [-Wmaybe-uninitialized]
     double midx=(nx+mx)/2,midy=(ny+my)/2;
                                ~~~^~~~
/in/foo.cc:41:20: warning: 'nx' may be used uninitialized in this function [-Wmaybe-uninitialized]
     double midx=(nx+mx)/2,midy=(ny+my)/2;
                 ~~~^~~~