Compilare: user.cpp: In function ‘void add(trie*, int)’: user.cpp:72:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (poz==s.size()) ^ user.cpp: In function ‘void make_cf()’: user.cpp:89:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<s.size();j++) ^ user.cpp: In function ‘void change(trie*, int, int)’: user.cpp:104:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (poz==s.size()) ^ user.cpp: In function ‘void write()’: user.cpp:122:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<s.size();i++) ^ user.cpp: In function ‘int main()’: user.cpp:152:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("fbsearch.in","r",stdin); ^ user.cpp:153:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("fbsearch.out","w",stdout); ^