Compilare: user.cpp: In function ‘int makenumber(std::string)’: user.cpp:8: warning: comparisons like ‘X<=Y<=Z’ do not have their mathematical meaning user.cpp:8: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:23: warning: comparisons like ‘X<=Y<=Z’ do not have their mathematical meaning user.cpp:28: warning: comparison between signed and unsigned integer expressions user.cpp:29: warning: comparisons like ‘X<=Y<=Z’ do not have their mathematical meaning user.cpp:33: warning: comparisons like ‘X<=Y<=Z’ do not have their mathematical meaning user.cpp:33: warning: comparison between signed and unsigned integer expressions