Compilare: user.cpp: In function ‘int main()’: user.cpp:51: warning: format ‘%ld’ expects type ‘long int’, but argument 2 has type ‘int’ user.cpp:54: warning: format ‘%ld’ expects type ‘long int’, but argument 2 has type ‘int’ user.cpp:54: warning: format ‘%ld’ expects type ‘long int’, but argument 3 has type ‘int’ user.cpp:15: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result