Compilare: main.cpp: In function 'int get_flow()': main.cpp:116:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 0; j < adj[D].size(); ++j) ~~^~~~~~~~~~~~~~~ main.cpp: At global scope: main.cpp:151:6: 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); ^