Compilare: user.cpp: In function ‘void ciur()’: user.cpp:29:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=2;i<=x;i++) ^ user.cpp:34:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=i;j<=x;j=j+i) ^ user.cpp: In function ‘int main()’: user.cpp:48:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1;i<=x;i++) ^