View Compilation Error

0_0_29652245_21010.cpp: In function 'int main()':
0_0_29652245_21010.cpp:36:37: error: 'f' was not declared in this scope
         std::memset(flag, 0, sizeof f);
                                     ^
0_0_29652245_21010.cpp:37:9: error: 'set' has not been declared
         set::memset(mem, 0, sizeof m);
         ^
0_0_29652245_21010.cpp:37:36: error: 'm' was not declared in this scope
         set::memset(mem, 0, sizeof m);
                                    ^
0_0_29652245_21010.cpp:38:9: error: 'cout' was not declared in this scope
         cout << dfs(0) << std::endl;
         ^
0_0_29652245_21010.cpp:38:9: note: suggested alternative:
In file included from 0_0_29652245_21010.cpp:1:0:
GCC4.9.2/x86_64-w64-mingw32/include/c++/iostream:61:18: note:   'std::cout'
   extern ostream cout;  /// Linked to standard output
                  ^