Compilare: user.cpp: In function ‘long long int catalan_(int)’: user.cpp:36: warning: unused variable ‘C’ user.cpp: In function ‘int main()’: user.cpp:54: warning: format ‘%d’ expects type ‘int’, but argument 2 has type ‘long long int’ user.cpp:50: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:51: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:53: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result