Compilare: user.cpp: In function ‘bool cautare(int)’: user.cpp:20:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<v[z].size();++i) ^ user.cpp: In function ‘void pop(int)’: user.cpp:37:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<v[z].size();++i) ^