View Compilation Error

0_0_35310495_21172.cpp: In function 'void out(int)':
0_0_35310495_21172.cpp:16:6: error: 'pre' was not declared in this scope
  out(pre[i]);
      ^
0_0_35310495_21172.cpp: In function 'int main()':
0_0_35310495_21172.cpp:54:13: error: 'pre' was not declared in this scope
         out(pre[n+1]);
             ^