View Compilation Error

0_0_21517940_14750.cpp: In function 'void do_dfs()':
0_0_21517940_14750.cpp:96:35: error: 'memset' was not declared in this scope
         memset(vis, 1, sizeof(vis));
                                   ^
0_0_21517940_14750.cpp: In function 'int main()':
0_0_21517940_14750.cpp:109:35: error: 'memset' was not declared in this scope
     memset(prime, 0, sizeof(prime));
                                   ^