Compilare: user.cpp: In function ‘void recursiv(long int)’: user.cpp:14:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( long i = 0 ; i < c [ a ] . size ( ) ; ++ i ) ^ user.cpp: In function ‘int main()’: user.cpp:27:43: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( "timbre.in" , "r" , stdin ) ; ^ user.cpp:28:45: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ( "timbre.out" , "w" , stdout ) ; ^ user.cpp:29:47: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%ld %ld %ld" , & n , & m , & k ) ; ^ user.cpp:33:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ( "%ld %ld" , & a , & b ) ; ^