View Compilation Error

0_0_24154068_21006.c:9:6: error: variably modified 'ch' at file scope
  int ch[maxn][sets];
      ^
0_0_24154068_21006.c:9:6: error: variably modified 'ch' at file scope
0_0_24154068_21006.c:10:6: error: variably modified 'val' at file scope
  int val[maxn];
      ^
0_0_24154068_21006.c:13:17: error: expected ':', ',', ';', '}' or '__attribute__' before '{' token
  int idx(char c){return c - 'a';}
                 ^
0_0_24154068_21006.c:53:1: error: unknown type name 'trie'
 trie t;
 ^
0_0_24154068_21006.c: In function 'main':
0_0_24154068_21006.c:58:3: error: request for member 'init' in something not a structure or union
  t.init();
   ^
0_0_24154068_21006.c:66:4: error: request for member 'insert' in something not a structure or union
   t.insert(buf);
    ^
0_0_24154068_21006.c:71:18: error: request for member 'query' in something not a structure or union
   printf("%d\n",t.query(buf));
                  ^