Compilare: main.cpp: In function 'int nextElem(std::vector<int>&)': main.cpp:15:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < cache.size(); i++) { ~~^~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:47:32: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen(INFILE, "r", stdin); ^ main.cpp:48:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen(OUTFILE, "w", stdout); ^