Compilare: user.cpp: In function ‘int main()’: user.cpp:24: warning: comparison between signed and unsigned integer expressions user.cpp:12: warning: unused variable ‘p’ user.cpp:8: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:9: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:14: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:15: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result user.cpp:11: warning: ‘len’ may be used uninitialized in this function