Compilare: user.cpp: In function ‘std::vector<int> transform(std::string)’: user.cpp:18:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<part.size(); i++) A[A.size()-1] = A[A.size()-1]*10 + int(part[i]) - 48; ^ user.cpp: In function ‘std::vector<int> product(std::vector<int>, int)’: user.cpp:30:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<A.size(); i++) { ^ user.cpp: In function ‘std::vector<int> diff(std::vector<int>, std::vector<int>)’: user.cpp:45:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<B.size(); i++) { ^ user.cpp:51:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=B.size(); i<A.size(); i++) { ^ user.cpp: In function ‘std::vector<int> sum(std::vector<int>, int)’: user.cpp:65:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0; i<A.size(); i++) { ^