Eroare de compilare: user.cpp:9:19: error: ‘double y1’ redeclared as different kind of symbol double xc,yc,r,x1,y1,x2,y2; ^ In file included from /usr/include/features.h:357:0, from /usr/include/i386-linux-gnu/c++/4.8/bits/os_defines.h:39, from /usr/include/i386-linux-gnu/c++/4.8/bits/c++config.h:420, from /usr/include/c++/4.8/iosfwd:38, from /usr/include/c++/4.8/ios:38, from /usr/include/c++/4.8/istream:38, from /usr/include/c++/4.8/fstream:38, from user.cpp:1: /usr/include/i386-linux-gnu/bits/mathcalls.h:243:1: error: previous declaration of ‘double y1(double)’ __MATHCALL (y1,, (_Mdouble_)); ^ user.cpp: In function ‘double f(double)’: user.cpp:16:81: error: invalid operands of types ‘double’ and ‘double(double)throw ()’ to binary ‘operator-’ return sq(r*cos(angle)+xc-x1) + sq(r*cos(angle)+xc-x2) + sq(r*sin(angle)+yc-y1) + sq(r*sin(angle)+yc-y2); ^ user.cpp: In function ‘int main()’: user.cpp:36:26: error: cannot bind ‘std::basic_istream<char>::__istream_type {aka std::basic_istream<char>}’ lvalue to ‘std::basic_istream<char>&&’ fin >> xc >> yc >> r >> x1 >> y1 >> x2 >> y2; ^ In file included from /usr/include/c++/4.8/fstream:38:0, from user.cpp:1: /usr/include/c++/4.8/istream:872:5: error: initializing argument 1 of ‘std::basic_istream<_CharT, _Traits>& std::operator>>(std::basic_istream<_CharT, _Traits>&&, _Tp&) [with _CharT = char; _Traits = std::char_traits<char>; _Tp = double(double)throw ()]’ operator>>(basic_istream<_CharT, _Traits>&& __is, _Tp& __x) ^ user.cpp: In function ‘double f(double)’: user.cpp:17:1: warning: control reaches end of non-void function [-Wreturn-type] } ^