View Compilation Error

0_0_30280589_11780.cpp:29:13: error: variable or field 'change' declared void
 void change(complex x[],int len)
             ^
0_0_30280589_11780.cpp:29:13: error: reference to 'complex' is ambiguous
0_0_30280589_11780.cpp:8:8: note: candidates are: struct complex
 struct complex
        ^
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/ccomplex:38:0,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/x86_64-w64-mingw32/bits/stdc++.h:52,
                 from 0_0_30280589_11780.cpp:1:
GCC4.9.2/x86_64-w64-mingw32/include/c++/complex:63:32: note:                 template<class _Tp> struct std::complex
   template<typename _Tp> class complex;
                                ^
0_0_30280589_11780.cpp:29:25: error: expected primary-expression before 'int'
 void change(complex x[],int len)
                         ^