Eroare de compilare: user.cpp: In function ‘unsigned int abs(int)’: user.cpp:12:19: error: new declaration ‘unsigned int abs(int)’ unsigned abs(int x) ^ In file included from /usr/include/c++/4.8/cstdlib:72:0, from /usr/include/c++/4.8/ext/string_conversions.h:41, from /usr/include/c++/4.8/bits/basic_string.h:2815, from /usr/include/c++/4.8/string:52, from /usr/include/c++/4.8/bits/locale_classes.h:40, from /usr/include/c++/4.8/bits/ios_base.h:41, from /usr/include/c++/4.8/ios:42, from /usr/include/c++/4.8/ostream:38, from /usr/include/c++/4.8/iostream:39, from user.cpp:1: /usr/include/stdlib.h:771:12: error: ambiguates old declaration ‘int abs(int)’ extern int abs (int __x) __THROW __attribute__ ((__const__)) __wur; ^ user.cpp: In function ‘int main()’: user.cpp:48:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("c.in","r",stdin); ^