Compilare: user.cpp: In function 'void print(std::vector<int, std::allocator<int> >)': user.cpp:35: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'std::vector<int, std::allocator<int> > eval(char*, int, int)': user.cpp:80: warning: comparison between signed and unsigned integer expressions user.cpp:87: warning: comparison between signed and unsigned integer expressions user.cpp:94: warning: comparison between signed and unsigned integer expressions user.cpp:100: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'int main()': user.cpp:125: warning: comparison between signed and unsigned integer expressions /tmp/cc6iXTGu.o: In function `main': user.cpp:(.text+0x95f): warning: the `gets' function is dangerous and should not be used.