View Compilation Error

0_0_28015567_32054.cpp: In function 'void initgraph()':
0_0_28015567_32054.cpp:28:36: error: 'memset' was not declared in this scope
     memset(first, -1, sizeof(first));
                                    ^
0_0_28015567_32054.cpp: In function 'void findcore()':
0_0_28015567_32054.cpp:77:35: error: 'memset' was not declared in this scope
     memset(vis, false, sizeof(vis));
                                   ^