Compilare: main.cpp: In function 'void add_edge(int, int, int)': main.cpp:84:33: warning: narrowing conversion of 'edges.std::vector<_Tp, _Alloc>::size<Edge, std::allocator<Edge> >()' from 'std::vector<Edge>::size_type {aka long unsigned int}' to 'int' inside { } [-Wnarrowing] Edge aux = {x, y, c, edges.size()}; ~~~~~~~~~~^~ main.cpp:85:36: warning: narrowing conversion of '(edges.std::vector<_Tp, _Alloc>::size<Edge, std::allocator<Edge> >() + 1ul)' from 'std::vector<Edge>::size_type {aka long unsigned int}' to 'int' inside { } [-Wnarrowing] Edge rev = {y, x, 0, edges.size() + 1}; ~~~~~~~~~~~~~^~~ main.cpp: At global scope: main.cpp:156:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type] main() ^ main.cpp: In member function 'char InParser::read_ch()': main.cpp:15:29: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, 4096, fin); ^