View Compilation Error

0_0_35336844_10114.cpp: In function 'int spfa(int)':
0_0_35336844_10114.cpp:28:28: error: 'memset' was not declared in this scope
  memset(vis, 0, sizeof(vis));
                            ^
0_0_35336844_10114.cpp: In function 'int main()':
0_0_35336844_10114.cpp:65:32: error: 'memset' was not declared in this scope
   memset(head, -1, sizeof(head));
                                ^