Compilare: user.cpp: In function ‘void read()’: user.cpp:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘int main()’: user.cpp:63: warning: comparison between signed and unsigned integer expressions user.cpp:57: warning: unused variable ‘l’