Compilare: user.cpp: In function ‘void rec(int, std::string)’: user.cpp:16:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(s.size()>L[t] || ok==1)return; ^ user.cpp:18:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(!islet(s[i]) && i<s.size() && a[i+1]==s[i]-'0') ^ user.cpp:20:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(!islet(s[i]) && i<s.size() && a[i+1]!=s[i]-'0')return ; ^ user.cpp:21:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i==s.size()) ^ user.cpp:23:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(s.size()==L[t])ok=1; ^ user.cpp:34:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i+1<s.size()) ^