View Compilation Error

0_0_30201462_31301.cpp: In function 'int Find(int)':
0_0_30201462_31301.cpp:22:17: error: expected primary-expression before ']' token
  while(x != pre[]) x = pre[x];
                 ^
0_0_30201462_31301.cpp:23:14: error: expected ')' before '{' token
  while(p != x{
              ^