Eroare de compilare: user.cpp: In function ‘long long int abs(int)’: user.cpp:6:21: error: ambiguating new declaration of ‘long long int abs(int)’ long long abs (int x) { ^ In file included from /usr/include/c++/5/cstdlib:72:0, from /usr/include/c++/5/ext/string_conversions.h:41, from /usr/include/c++/5/bits/basic_string.h:5249, from /usr/include/c++/5/string:52, from /usr/include/c++/5/bits/locale_classes.h:40, from /usr/include/c++/5/bits/ios_base.h:41, from /usr/include/c++/5/ios:42, from /usr/include/c++/5/istream:38, from /usr/include/c++/5/fstream:38, from user.cpp:1: /usr/include/stdlib.h:774:12: note: old declaration ‘int abs(int)’ extern int abs (int __x) __THROW __attribute__ ((__const__)) __wur; ^