Compilare: main.cpp: In function 'std::vector<int> rank_cats(std::vector<int>, std::vector<int>, std::vector<int>)': main.cpp:16:25: warning: unused variable 'z' [-Wunused-variable] int n , i , x , y , z , now12 , now23 , now13; ^ main.cpp:16:29: warning: unused variable 'now12' [-Wunused-variable] int n , i , x , y , z , now12 , now23 , now13; ^~~~~ main.cpp:16:37: warning: unused variable 'now23' [-Wunused-variable] int n , i , x , y , z , now12 , now23 , now13; ^~~~~ main.cpp:16:45: warning: unused variable 'now13' [-Wunused-variable] int n , i , x , y , z , now12 , now23 , now13; ^~~~~ main.cpp: In member function 'char InParser::read_ch()': main.cpp:67:29: 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); ^