Compilare: main.cpp: In function 'bool subseq(const string&, const string&)': main.cpp:12:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < a.size() && j < b.size()) { ~~^~~~~~~~~~ main.cpp:12:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while (i < a.size() && j < b.size()) { ~~^~~~~~~~~~ main.cpp:17:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] return j == b.size(); ~~^~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:21:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("interesant.in", "r", stdin); ^ main.cpp:22:43: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("interesant.out", "w", stdout); ^