View Compilation Error

0_0_21195113_18042.cpp: In function 'int main()':
0_0_21195113_18042.cpp:40:31: error: 'memset' was not declared in this scope
         memset(fa,0,sizeof(fa));
                               ^
0_0_21195113_18042.cpp:49:19: error: reference to 'hash' is ambiguous
             thash=hash(telf);
                   ^
0_0_21195113_18042.cpp:21:5: note: candidates are: int hash(int)
 int hash(int k){
     ^
In file included from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/basic_string.h:3068:0,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/string:52,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/locale_classes.h:40,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/ios_base.h:41,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/ios:42,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/ostream:38,
                 from GCC4.9.2/x86_64-w64-mingw32/include/c++/iostream:39,
                 from 0_0_21195113_18042.cpp:1:
GCC4.9.2/x86_64-w64-mingw32/include/c++/bits/functional_hash.h:58:12: note:                 template<class _Tp> struct std::hash
     struct hash;
            ^