View Compilation Error

0_0_21277069_11995.cpp: In function 'bool bfs()':
0_0_21277069_11995.cpp:35:28: error: 'memset' was not declared in this scope
  memset(vis, 0, sizeof(vis));
                            ^
0_0_21277069_11995.cpp: In function 'int maxflow(int, int)':
0_0_21277069_11995.cpp:74:29: error: 'memset' was not declared in this scope
   memset(cur, 0, sizeof(cur));
                             ^
0_0_21277069_11995.cpp: In function 'bool find_scc(int)':
0_0_21277069_11995.cpp:112:28: error: 'memset' was not declared in this scope
  memset(num, 0, sizeof(num));
                            ^