Eroare de compilare: user.cpp: In function ‘long long int abs(int)’: user.cpp:24:11: error: ambiguating new declaration of ‘long long int abs(int)’ long long abs(int a) ^~~ In file included from /usr/include/c++/6/cstdlib:75:0, from /usr/include/c++/6/ext/string_conversions.h:41, from /usr/include/c++/6/bits/basic_string.h:5417, from /usr/include/c++/6/string:52, from /usr/include/c++/6/bits/locale_classes.h:40, from /usr/include/c++/6/bits/ios_base.h:41, from /usr/include/c++/6/ios:42, from /usr/include/c++/6/istream:38, from /usr/include/c++/6/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; ^~~