Compilare: main.cpp: In function 'int main()': main.cpp:102:34: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d %d " ,&type,&t); ^ main.cpp: In function 'void read(int&, std::vector<std::pair<int, int> >&)': main.cpp:14:25: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d " ,&n); ^ main.cpp:17:58: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d %d " ,&pts[i].first,&pts[i].second); ^ main.cpp: In function 'int main()': main.cpp:81:37: warning: 'nod' may be used uninitialized in this function [-Wmaybe-uninitialized] edges.push_back({nod, id[nod]}); ^ main.cpp:73:13: note: 'nod' was declared here int nod; ^~~