/in/foo.cc: In function 'bool cmp(lx, lx)':
/in/foo.cc:12:20: error: 'sqr' was not declared in this scope
     return (sqr(a.x)+sqr(a.y))<(sqr(b.x)+sqr(b.y));
                    ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:22:33: error: 'sqr' was not declared in this scope
     ans=sqrt(sqr((p[n].x-p[1].x))+sqr((p[n].y-p[1].y)));
                                 ^