Compilare: user.cpp: In function ‘unsigned int suma(unsigned int, unsigned int)’: user.cpp:12:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=a; i<=b; i++) ^ user.cpp: In function ‘int main()’: user.cpp:20:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1; i<=n; i++) ^