Compilare: user.cpp: In function ‘void add(std::string&, int, int)’: user.cpp:38:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int j = 0; j < graph[nod].size() && !found; ++j ) ^ user.cpp:47:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if( x >= s.size() - 1 ) ^ user.cpp:61:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if( x >= s.size() - 1 ) ^ user.cpp: In function ‘int main()’: user.cpp:85:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < str.size(); ++i ) ^ user.cpp:93:49: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int j = 0; j < graph[nod].size(); ++j ) ^