View Compilation Error

0_0_13802625_3150.cpp: In function 'void rotate(Node*&, int)':
0_0_13802625_3150.cpp:36:13: error: 'o' was not declared in this scope
     Node* k=o->ch[d^1];
             ^
0_0_13802625_3150.cpp: In function 'void remove(Node*&, int)':
0_0_13802625_3150.cpp:70:23: error: 'ch' was not declared in this scope
             int d2=(o>ch[0]>o->ch[1])?1:0;
                       ^
0_0_13802625_3150.cpp: In function 'int kth(Node*&, int)':
0_0_13802625_3150.cpp:84:10: error: 'ch' was not declared in this scope
     if(o>ch[0] == NULL)
          ^