Compilare: user.cpp: In function ‘void read()’: user.cpp:18:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < a.size(); cin >> a[i++]); ^ user.cpp:19:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < b.size(); cin >> b[i++]); ^ user.cpp: In function ‘void solve()’: user.cpp:25:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < x.size(); x[i++].resize(b.size())); // x matrice a.size() x b.size() ^ user.cpp:27:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < x[0].size(); i++) ^ user.cpp:30:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < x.size(); i++) ^ user.cpp:33:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i < x.size(); i++) ^ user.cpp:34:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 1; j < x[i].size(); j++) ^