Compilare: user.cpp: In function ‘int main()’: user.cpp:9: warning: comparison between signed and unsigned integer expressions user.cpp:12: warning: format ‘%d’ expects type ‘int’, but argument 2 has type ‘long long unsigned int’ user.cpp:3: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:4: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:7: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result