Compilare: user.cpp: In function ‘int main()’: user.cpp:74: warning: operation on ‘l’ may be undefined user.cpp:58: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:59: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:62: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:65: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:70: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result