Compilare: main.cpp: In member function 'Arc* Vertex::getNextArc()': main.cpp:93:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(currentArc == incidentFromArcs.size()) { ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp: In member function 'void Vertex::moveToNextArc()': main.cpp:102:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(currentArc == incidentFromArcs.size()) { ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:145:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("maxflow.in","r",stdin); ^ main.cpp:146:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("maxflow.out","w",stdout); ^ main.cpp:148:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&N,&M); ^ main.cpp:161:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d",&x,&y,&capacity); ^