Compilare: user.cpp: In function ‘int main()’: user.cpp:51:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 1600; j <=elements.size()&&x>=elements[j].value; j--) ^ user.cpp:87:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < elements.size(); i++) ^ user.cpp:96:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < elements.size(); i++) ^