Compilare: user.cpp: In function ‘int check_condition(std::string&, bool*, int)’: user.cpp:18:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(; i < s.length() ; ++i){ ^ user.cpp: In function ‘std::string check_sol(std::string&, std::string&)’: user.cpp:36:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0 ; i < s.length(); ++i) ^ user.cpp: In function ‘int main()’: user.cpp:83:5: warning: unused variable ‘b’ [-Wunused-variable] int b= 2; ^