Compilare: user.cpp: In function ‘int main()’: user.cpp:126:59: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(C[i] == 0 && a.size() == b.size() && n - i == a.size()) ^ user.cpp:211:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(n - i == b.size()) B[i] = 1; ^ user.cpp:227:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(n - i == a.size()) A[i] = 1; ^