Compilare: user.cpp: In function ‘int main()’: user.cpp:14:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( i = 2; i*i <= n; ++i) ^ user.cpp:18:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = i*i; j <= n; j += i) ^ user.cpp:24:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<n;i++) ^