Compilare: user.cpp: In function ‘Node* insert(Node*, char)’: user.cpp:38:23: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (trie->children[c] == NULL) ^ user.cpp:39:21: warning: array subscript has type ‘char’ [-Wchar-subscripts] trie->children[c] = newNode(trie); ^ user.cpp:40:26: warning: array subscript has type ‘char’ [-Wchar-subscripts] return trie->children[c]; ^ user.cpp: In function ‘int main()’: user.cpp:111:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ratina.out", "w", stdout); ^ user.cpp: In member function ‘char InParser::read_ch()’: user.cpp:78:32: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, 4096, fin); ^