View Compilation Error

0_0_33653697_23995.cpp: In function 'Point Polygon_center(Point*, int)':
0_0_33653697_23995.cpp:233:23: error: 'o' was not declared in this scope
         ans=ans+(p[i]+o[(i+1)%n])*Cross(p[i],p[(i+1)%n]);
                       ^