Compilare: main.cpp: In function 'std::vector<int> rank_cats(std::vector<int>, std::vector<int>, std::vector<int>)': main.cpp:28:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<p.size();i++) poz[0][p[i]] = poz[1][f[i]] = poz[2][d[i]] = i+1; ~^~~~~~~~~ main.cpp: In member function 'char InParser::read_ch()': main.cpp:57:29: 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); ^