Compilare: user.cpp: In function ‘int last()’: user.cpp:21:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=c.size()-n+1;i<=c.size();i++){ ^ user.cpp: In function ‘void rec()’: user.cpp:31:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(c.size()==lim){ ^ user.cpp:32:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<c.size();i++){ ^