Compilare: user.cpp: In function ‘int main()’: user.cpp:20:8: warning: statement is a reference, not call, to function ‘exit’ [-Waddress] exit; ^ user.cpp:20:8: warning: statement has no effect [-Wunused-value] user.cpp:25:8: warning: statement is a reference, not call, to function ‘exit’ [-Waddress] exit; ^ user.cpp:25:8: warning: statement has no effect [-Wunused-value] user.cpp:30:8: warning: statement is a reference, not call, to function ‘exit’ [-Waddress] exit; ^ user.cpp:30:8: warning: statement has no effect [-Wunused-value]