Compilare: user.cpp: In function ‘int number(int)’: user.cpp:22:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0; j<h[zona].size(); j++) ^ user.cpp: In function ‘int main()’: user.cpp:62:18: warning: unused variable ‘a’ [-Wunused-variable] int i, l, c, a, b; ^ user.cpp:62:21: warning: unused variable ‘b’ [-Wunused-variable] int i, l, c, a, b; ^