Compilare: user.cpp: In function ‘void DFs(long int)’: user.cpp:41: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void DFs_2(long int)’: user.cpp:84: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘int main()’: user.cpp:131: warning: format ‘%d’ expects type ‘int’, but argument 2 has type ‘long int’ user.cpp:105: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:106: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result