Compilare: user.cpp: In function `int ok()': user.cpp:11: warning: NULL used in arithmetic user.cpp: In function `int main()': user.cpp:19: warning: converting to `long int' from `double' user.cpp:23: warning: converting to `int' from `double' user.cpp:28: warning: converting to `int' from `double' user.cpp:33: warning: converting to `int' from `double' user.cpp:37: warning: converting to `int' from `double' user.cpp:55:2: warning: no newline at end of file