View Compilation Error

0_0_13685507_21815.cpp: In function 'void calprime()':
0_0_13685507_21815.cpp:12:35: error: 'memset' was not declared in this scope
     memset(flag,false,sizeof(flag));
                                   ^
0_0_13685507_21815.cpp: In function 'int main()':
0_0_13685507_21815.cpp:87:29: error: 'memset' was not declared in this scope
         memset(p,0,sizeof(p));
                             ^