Compilare: user.cpp: In function ‘int main()’: user.cpp:51:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j < elements.size() && x >= elements[j].value; j++) ^ user.cpp:75:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < elements.size(); i++) ^ user.cpp:84:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i < elements.size(); i++) ^