View Compilation Error

0_0_32680569_14621.cpp: In function 'int main()':
0_0_32680569_14621.cpp:68:20: error: 'cmpxy' was not declared in this scope
         sort(p,p+n,cmpxy);                          //先排序
                    ^
0_0_32680569_14621.cpp:69:43: error: 'Closest_Pair' was not declared in this scope
         printf("%.2f\n",Closest_Pair(0,n-1)/2); //输出最短距离的一半
                                           ^