Compilare: main.cpp: In function 'int main()': main.cpp:34:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < vec.size(); i++){ ~~^~~~~~~~~~~~ main.cpp:36:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j < vec.size() && vec[j].fi == vec[i].fi) ~~^~~~~~~~~~~~ main.cpp:42:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j + 1 == vec.size()) { ~~~~~~^~~~~~~~~~~~~ main.cpp:69:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < fuel.size(); i++) ~~^~~~~~~~~~~~~ main.cpp:24:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("xmoto.in", "r", stdin); ^ main.cpp:25:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("xmoto.out", "w", stdout); ^