Compilare: user.cpp: In function ‘int main()’: user.cpp:16:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=1;j<s.size();j++) ^ user.cpp:19:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(r<s.size() && s[r]==s[r-l])r++; ^ user.cpp:26:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(r<s.size() && s[r]==s[r-l])r++; ^ user.cpp:31:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<s.size();j++) ^