Compilare: main.cpp: In function 'void proc(const string&, std::vector<int>&)': main.cpp:38:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0;i < s.size();++i) ~~^~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:55:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("triangles.in", "r", stdin); ^ main.cpp:56:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("triangles.out", "w", stdout); ^