View Compilation Error

0_0_31389917_7172.cpp: In function 'int main()':
0_0_31389917_7172.cpp:12:36: error: 'memset' was not declared in this scope
 #define mem(a) memset(a,0,sizeof(a))
                                    ^
0_0_31389917_7172.cpp:60:3: note: in expansion of macro 'mem'
   mem(a),mem(vis),mem(dp);
   ^