View Compilation Error

0_0_33826167_14024.cpp: In function 'int GetSG(int)':
0_0_33826167_14024.cpp:15:38: error: 'memset' was not declared in this scope
  memset(visited,false,sizeof(visited));
                                      ^
0_0_33826167_14024.cpp:20:6: error: 'i' was not declared in this scope
  for(i=0;;i++)
      ^
0_0_33826167_14024.cpp:23:17: error: 'i' was not declared in this scope
   return SG[id]=i;
                 ^
0_0_33826167_14024.cpp: In function 'int main()':
0_0_33826167_14024.cpp:43:26: error: 'memset' was not declared in this scope
   memset(SG,-1,sizeof(SG));
                          ^